U.S. patent application number 15/588417 was filed with the patent office on 2017-08-17 for data transmission method and data transmission device.
The applicant listed for this patent is Huawei Technologies Co., Ltd.. Invention is credited to Lei GUAN, Qiang LI, Sha MA, Zuomin WU, Juan ZHENG.
Application Number | 20170237463 15/588417 |
Document ID | / |
Family ID | 55908448 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170237463 |
Kind Code |
A1 |
ZHENG; Juan ; et
al. |
August 17, 2017 |
DATA TRANSMISSION METHOD AND DATA TRANSMISSION DEVICE
Abstract
Embodiments of the present invention provide a data transmission
method and a data transmission device. The data transmission device
includes: a detection unit, configured to detect a first signal in
a first cell; a determining unit, configured to determine a
reference time point according to a first sequence of the detected
first signal, where the reference time point is located in a first
subframe of the first cell; where the determining unit is further
configured to determine a position of a data channel according to
the determined reference time point; and a receiving unit,
configured to receive, according to the position of the data
channel, control data and/or service data carried on the data
channel. According to the embodiments of the present invention,
resource utilization can be improved.
Inventors: |
ZHENG; Juan; (Beijing,
CN) ; WU; Zuomin; (Beijing, CN) ; GUAN;
Lei; (Beijing, CN) ; LI; Qiang; (Shenzhen,
CN) ; MA; Sha; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Huawei Technologies Co., Ltd. |
Shenzhen |
|
CN |
|
|
Family ID: |
55908448 |
Appl. No.: |
15/588417 |
Filed: |
May 5, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/CN2014/090655 |
Nov 7, 2014 |
|
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15588417 |
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Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04L 5/0048 20130101;
H04W 16/14 20130101; H04L 5/0053 20130101; H04L 5/0044 20130101;
H04B 1/7087 20130101; H04L 5/001 20130101; H04W 56/00 20130101;
H04L 27/0006 20130101 |
International
Class: |
H04B 1/7087 20060101
H04B001/7087; H04L 5/00 20060101 H04L005/00; H04W 16/14 20060101
H04W016/14 |
Claims
1. A data transmission device, comprising: a processor, configured
to detect a first signal in a first cell; the processor, further
configured to determine a reference time point according to a first
sequence of the detected first signal, wherein the reference time
point is located in a first subframe of the first cell; wherein the
processor is further configured to determine a position of a data
channel according to the determined reference time point; and a
receiver, configured to receive, according to the position of the
data channel, control data and/or service data carried on the data
channel.
2. The data transmission device according to claim 1, wherein the
processor is further configured to determine the reference time
point according to a one-to-one correspondence between sequence
information of the first sequence and the reference time point.
3. The data transmission device according to claim 1, wherein the
processor is further configured to: if a time length between the
determined reference time point and an end boundary of the first
subframe is not less than X1, determine that the position of the
data channel is located in the first subframe, wherein X1 is a time
length that is not less than 0.
4. The data transmission device according to claim 1, wherein the
processor is further configured to: if a time length between the
determined reference time point and an end boundary of the first
subframe is less than X2, determine that the position of the data
channel is located in a second subframe, wherein the second
subframe is a next subframe adjacent to the first subframe; or if a
time length between the determined reference time point and an end
boundary of the first subframe is less than X2, determine that the
position of the data channel is located in a third subframe,
wherein the third subframe is a next subframe that is in the second
cell and adjacent to the first subframe in time, and the second
cell and the first cell are deployed on different spectrum
resources; wherein X2 is a time length that is not less than 0.
5. The data transmission device according to claim 1, wherein the
processor is further configured to: if a time length between the
determined reference time point and an end boundary of the first
subframe is less than X3, and the time length between the
determined reference time point and the end boundary of the first
subframe is greater than Y4, determine that the position of the
data channel is located in the first subframe, wherein X3 and Y4
are time lengths that are not less than 0, and Y4 is not greater
than X3.
6. A data transmission device, comprising: a processor, configured
to determine a reference time point, wherein the reference time
point is located in a first subframe of a first cell; wherein the
processor is further configured to determine a sending position of
a first signal according to the reference time point; and a
transmitter, configured to send the first signal in the sending
position of the first signal; wherein the processor is further
configured to determine a position of a data channel according to
the reference time point; and the transmitter is further configured
to send, in the position of the data channel, control data and/or
service data carried on the data channel.
7. The data transmission device according to claim 6, wherein the
first signal comprises or carries a first sequence; and the
processor is further configured to determine the first sequence
according to the reference time point.
8. The data transmission device according to claim 6, wherein the
processor is further configured to: if a time length between the
reference time point and an end boundary of the first subframe is
not less than X1, determine that the position of the data channel
is located in the first subframe, wherein X1 is a time length that
is not less than 0.
9. The data transmission device according to claim 6, wherein the
processor is configured further to: if a time length between the
reference time point and an end boundary of the first subframe is
less than X2, determine that the position of the data channel is
located in a second subframe, wherein the second subframe is a next
subframe adjacent to the first subframe; or if a time length
between the reference time point and an end boundary of the first
subframe is less than X2, determine that the position of the data
channel is located in a third subframe, wherein the third subframe
is a next subframe that is in the second cell and adjacent to the
first subframe in time, and the second cell and the first cell are
deployed on different spectrum resources; wherein X2 is a time
length that is not less than 0.
10. The data transmission device according to claim 6, wherein the
processor is further configured to: if a time length between the
reference time point and an end boundary of the first subframe is
less than X3, and the time length between the reference time point
and the end boundary of the first subframe is greater than Y4,
determine that the position of the data channel is located in the
first subframe, wherein X3 and Y4 are time lengths that are not
less than 0, and Y4 is not greater than X3.
11. A data transmission method, comprising: detecting a first
signal in a first cell; determining a reference time point
according to a first sequence of the detected first signal, wherein
the reference time point is located in a first subframe of the
first cell; determining a position of a data channel according to
the determined reference time point; and receiving, according to
the position of the data channel, control data and/or service data
carried on the data channel.
12. The method according to claim 11, wherein the determining a
reference time point according to the detected first sequence
comprises: determining the reference time point according to a
one-to-one correspondence between sequence information of the first
sequence and the reference time point.
13. The method according to claim 11, wherein the determining a
position of a data channel according to the determined reference
time point comprises: if a time length between the determined
reference time point and an end boundary of the first subframe is
not less than X1, determining that the position of the data channel
is located in the first subframe, wherein X1 is a time length that
is not less than 0.
14. The method according to claim 11, wherein the determining a
position of a data channel according to the determined reference
time point comprises: if a time length between the determined
reference time point and an end boundary of the first subframe is
less than X2, determining that the position of the data channel is
located in a second subframe, wherein the second subframe is a next
subframe adjacent to the first subframe; or if a time length
between the determined reference time point and an end boundary of
the first subframe is less than X2, determining that the position
of the data channel is located in a third subframe, wherein the
third subframe is a next subframe that is in the second cell and
adjacent to the first subframe in time, and the second cell and the
first cell are deployed on different spectrum resources; wherein X2
is a time length that is not less than 0.
15. The method according to claim 11, wherein the determining a
position of a data channel according to the determined reference
time point comprises: if a time length between the determined
reference time point and an end boundary of the first subframe is
less than X3, and the time length between the determined reference
time point and the end boundary of the first subframe is greater
than Y4, determining that the position of the data channel is
located in the first subframe, wherein X3 and Y4 are time lengths
that are not less than 0, and Y4 is not greater than X3.
16. A data transmission method, comprising: determining a reference
time point, wherein the reference time point is located in a first
subframe of a first cell; determining a sending position of a first
signal according to the reference time point, and sending the first
signal in the sending position of the first signal; and determining
a position of a data channel according to the reference time point,
and sending, in the determined position of the data channel,
control data and/or service data carried on the data channel.
17. The method according to claim 16, wherein the first signal
comprises or carries a first sequence; and the method further
comprises: determining the first sequence according to the
reference time point.
18. The method according to claim 16, wherein the determining a
position of a data channel according to the reference time point
comprises: if a time length between the reference time point and an
end boundary of the first subframe is not less than X1, determining
that the position of the data channel is located in the first
subframe, wherein X1 is a time length that is not less than 0.
19. The method according to claim 16, wherein the determining a
position of a data channel according to the reference time point
comprises: if a time length between the reference time point and an
end boundary of the first subframe is less than X2, determining
that the position of the data channel is located in a second
subframe, wherein the second subframe is a next subframe adjacent
to the first subframe; or if a time length between the reference
time point and an end boundary of the first subframe is less than
X2, determining that the position of the data channel is located in
a third subframe, wherein the third subframe is a next subframe
that is in the second cell and adjacent to the first subframe in
time, and the second cell and the first cell are deployed on
different spectrum resources; wherein X2 is a time length that is
not less than 0.
20. The method according to claim 16, wherein the determining a
position of a data channel according to the reference time point
comprises: if a time length between the reference time point and an
end boundary of the first subframe is less than X3, and the time
length between the reference time point and the end boundary of the
first subframe is greater than Y4, determining that the position of
the data channel is located in the first subframe, wherein X3 and
Y4 are time lengths that are not less than 0, and Y4 is not greater
than X3.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of International
Application No. PCT/CN2014/090655, filed on Nov. 7, 2014, the
disclosure of which is hereby incorporated by reference in its
entirety.
TECHNICAL FIELD
[0002] Embodiments of the present invention relate to the field of
mobile communications, and in particular, to a data transmission
method and a data transmission device.
BACKGROUND
[0003] A spectrum is a basis for wireless communication. Currently,
for using of a spectrum, there is a design that allows a device in
a Long Term Long (Long Term Long, LTE) system and a device in a
non-LTE system (for example, a Wireless Fidelity (Wireless
Fidelity, WiFi) device) to jointly use an unauthorized or
unlicensed (unlicensed) spectrum. Specifically, the LTE system may
use the unlicensed spectrum independently or in a form of a
secondary cell configuration. However, a problem urgently to be
resolved is to seek a data transmission method that can ensure
normal data communication between LTE devices while using the
unlicensed spectrum efficiently.
SUMMARY
[0004] Embodiments of the present invention provide a data
transmission method and a data transmission device, so that
resource utilization can be improved.
[0005] According to a first aspect, a data transmission device is
provided and includes: a detection unit, configured to detect a
first signal in a first cell; a determining unit, configured to
determine a reference time point according to a first sequence of
the detected first signal, where the reference time point is
located in a first subframe of the first cell; where the
determining unit is further configured to determine a position of a
data channel according to the determined reference time point; and
a receiving unit, configured to receive, according to the position
of the data channel, control data and/or service data carried on
the data channel.
[0006] With reference to the first aspect, in an implementation
manner, the determining unit is specifically configured to
determine the reference time point according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0007] With reference to the first aspect and the foregoing
implementation manner of the first aspect, in another
implementation manner, the determining unit is specifically
configured to determine the reference time point according to an
index of a symbol that is in the first cell and closest to a
position of the first sequence.
[0008] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is specifically
configured to determine the reference time point according to an
index of a symbol that is in a second cell and closest to a
position of the first sequence, where the second cell and the first
cell are deployed on different spectrum resources.
[0009] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the position of the first sequence includes
a start time position of the first sequence or an end time position
of the first sequence.
[0010] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is specifically
configured to: if a time length between the determined reference
time point and an end boundary of the first subframe is not less
than X1, determine that the position of the data channel is located
in the first subframe, where X1 is a time length that is not less
than 0.
[0011] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is further configured
to determine that a time length of a second signal is M1, where the
second signal includes the first signal, and M1 is a minimum time
length of the second signal.
[0012] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is specifically
configured to:
[0013] if a time length between the determined reference time point
and an end boundary of the first subframe is less than X2,
determine that the position of the data channel is located in a
second subframe, where the second subframe is a next subframe
adjacent to the first subframe; or
[0014] if a time length between the determined reference time point
and an end boundary of the first subframe is less than X2,
determine that the position of the data channel is located in a
third subframe, where the third subframe is a next subframe that is
in the second cell and adjacent to the first subframe in time, and
the second cell and the first cell are deployed on different
spectrum resources; where
[0015] X2 is a time length that is not less than 0.
[0016] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the determined reference time point
and the end boundary of the first subframe is not less than Y1,
determine that a time length of a second signal is Z1, where the
second signal includes the first signal, Z1 belongs to a length set
{L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of the
second signal is located at the end boundary of the first subframe,
where n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0017] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the determined reference time point
and the end boundary of the first subframe is less than Y2,
determine that a time length of a second signal is Z2, where the
second signal includes the first signal, Z2 belongs to a length
set, {L.sub.1', L.sub.2', . . . L.sub.n'}, an end time position of
the second signal is located in the second subframe of the first
cell, and the second subframe is the next subframe adjacent to the
first subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0018] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the determined reference time point
and the end boundary of the first subframe is less than Y3,
determine that a time length of a second signal is Z3, where the
second signal includes the first signal, Z3 is less than M2, an end
time position of the second signal is located at the end boundary
of the first subframe, M2 is a preset minimum time length of the
second signal, and Y3 is a time length that is not equal to X2 and
not less than 0.
[0019] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the determining unit is specifically
configured to: if a time length between the determined reference
time point and an end boundary of the first subframe is less than
X3, and the time length between the determined reference time point
and the end boundary of the first subframe is greater than Y4,
determine that the position of the data channel is located in the
first subframe, where X3 and Y4 are time lengths that are not less
than 0, and Y4 is not greater than X3.
[0020] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the data channel carries data scheduling
information of a second subframe of the first cell, where the
second subframe is a next subframe adjacent to the first
subframe.
[0021] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, a correspondence exists between the
reference time point and the position of the data channel, each
reference time point corresponds to one index, and each index
corresponds to one position of the data channel.
[0022] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the position of the data channel includes at
least one of the following positions: a position of a control data
channel or a position of a service data channel.
[0023] With reference to the first aspect and the foregoing
implementation manners of the first aspect, in another
implementation manner, the first cell is a cell on an unlicensed
spectrum.
[0024] According to a second aspect, a data transmission device is
provided and includes: a determining unit, configured to determine
a reference time point, where the reference time point is located
in a first subframe of a first cell; where the determining unit is
further configured to determine a sending position of a first
signal according to the reference time point; and a sending unit,
configured to send the first signal in the sending position of the
first signal; where the determining unit is further configured to
determine a position of a data channel according to the reference
time point; and the sending unit is further configured to send, in
the position of the data channel, control data and/or service data
carried on the data channel.
[0025] With reference to the second aspect, in an implementation
manner, the determining unit is specifically configured to
determine the reference time point according to an index of a
symbol closest to a time point at which a spectrum resource of the
first cell is preempted.
[0026] With reference to the second aspect and the foregoing
implementation manner of the second aspect, in another
implementation manner, the determining unit is specifically
configured to determine the reference time point according to an
index of a symbol that is in a second cell and closest to a time
point at which a spectrum resource of the first cell is preempted,
where the second cell and the first cell are deployed on different
spectrum resources.
[0027] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the first signal includes or carries a first
sequence; and the determining unit is further configured to
determine the first sequence according to the reference time
point.
[0028] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is specifically
configured to determine the first sequence according to a
one-to-one correspondence between sequence information of the first
sequence and the reference time point.
[0029] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is specifically
configured to: if a time length between the reference time point
and an end boundary of the first subframe is not less than X1,
determine that the position of the data channel is located in the
first subframe, where X1 is a time length that is not less than
0.
[0030] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is further configured
to determine that a time length of a second signal is M1, where the
second signal includes the first signal, and M1 is a minimum time
length of the second signal.
[0031] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is specifically
configured to:
[0032] if a time length between the reference time point and an end
boundary of the first subframe is less than X2, determine that the
position of the data channel is located in a second subframe, where
the second subframe is a next subframe adjacent to the first
subframe; or
[0033] if a time length between the reference time point and an end
boundary of the first subframe is less than X2, determine that the
position of the data channel is located in a third subframe, where
the third subframe is a next subframe that is in the second cell
and adjacent to the first subframe in time, and the second cell and
the first cell are deployed on different spectrum resources;
where
[0034] X2 is a time length that is not less than 0.
[0035] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the reference time point and the end
boundary of the first subframe is not less than Y1, determine that
a time length of a second signal is Z1, where the second signal
includes the first signal, Z1 belongs to a length set {L.sub.1,
L.sub.2, . . . L.sub.n}, and an end time position of the second
signal is located at the end boundary of the first subframe, where
n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0036] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the reference time point and the end
boundary of the first subframe is less than Y2, determine that a
time length of a second signal is Z2, where the second signal
includes the first signal, Z2 belongs to a length set {L.sub.1',
L.sub.2', . . . L.sub.n'}, an end time position of the second
signal is located in the second subframe of the first cell, and the
second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.k, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0037] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is further configured
to: if the time length between the reference time point and the end
boundary of the first subframe is less than Y3, determine that a
time length of a second signal is Z3, where the second signal
includes the first signal, Z3 is less than M2, an end time position
of the second signal is located at the end boundary of the first
subframe, M2 is a minimum time length of the second signal, and Y3
is a time length that is not equal to X2 and not less than 0.
[0038] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the determining unit is specifically
configured to: if a time length between the reference time point
and an end boundary of the first subframe is less than X3, and the
time length between the reference time point and the end boundary
of the first subframe is greater than Y4, determine that the
position of the data channel is located in the first subframe,
where X3 and Y4 are time lengths that are not less than 0, and Y4
is not greater than X3.
[0039] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the data channel carries data scheduling
information of a second subframe of the first cell, where the
second subframe is a next subframe adjacent to the first
subframe.
[0040] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, a correspondence exists between the
reference time point and the position of the data channel, each
reference time point corresponds to one index, and each index
corresponds to one position of the data channel.
[0041] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the position of the data channel includes at
least one of the following positions: a position of a control data
channel or a position of a service data channel.
[0042] With reference to the second aspect and the foregoing
implementation manners of the second aspect, in another
implementation manner, the first cell is a cell on an unlicensed
spectrum.
[0043] According to a third aspect, a data transmission method is
provided and includes: detecting a first signal in a first cell;
determining a reference time point according to a first sequence of
the detected first signal, where the reference time point is
located in a first subframe of the first cell; determining a
position of a data channel according to the determined reference
time point; and receiving, according to the position of the data
channel, control data and/or service data carried on the data
channel.
[0044] With reference to the third aspect, in an implementation
manner, the determining a reference time point according to the
detected first sequence includes: determining the reference time
point according to a one-to-one correspondence between sequence
information of the first sequence and the reference time point.
[0045] With reference to the third aspect and the foregoing
implementation manner of the third aspect, in another
implementation manner, the determining a reference time point
according to the detected first sequence includes: determining the
reference time point according to an index of a symbol that is in
the first cell and closest to a position of the first sequence.
[0046] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the determining a reference time point
according to the detected first sequence includes: determining the
reference time point according to an index of a symbol that is in a
second cell and closest to a position of the first sequence, where
the second cell and the first cell are deployed on different
spectrum resources.
[0047] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the position of the first sequence includes
a start time position of the first sequence or an end time position
of the first sequence.
[0048] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the determining a position of a data channel
according to the determined reference time point includes: if a
time length between the determined reference time point and an end
boundary of the first subframe is not less than X1, determining
that the position of the data channel is located in the first
subframe, where X1 is a time length that is not less than 0.
[0049] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the method further includes: determining
that a time length of a second signal is M1, where the second
signal includes the first signal, and M1 is a minimum time length
of the second signal.
[0050] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the determining a position of a data channel
according to the determined reference time point includes: if a
time length between the determined reference time point and an end
boundary of the first subframe is less than X2, determining that
the position of the data channel is located in a second subframe,
where the second subframe is a next subframe adjacent to the first
subframe; or if a time length between the determined reference time
point and an end boundary of the first subframe is less than X2,
determining that the position of the data channel is located in a
third subframe, where the third subframe is a next subframe that is
in the second cell and adjacent to the first subframe in time, and
the second cell and the first cell are deployed on different
spectrum resources; where X2 is a time length that is not less than
0.
[0051] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the method further includes: if the time
length between the determined reference time point and the end
boundary of the first subframe is not less than Y1, determining
that a time length of a second signal is Z1, where the second
signal includes the first signal, Z1 belongs to a length set
{L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of the
second signal is located at the end boundary of the first subframe,
where n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0052] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the method further includes: if the time
length between the determined reference time point and the end
boundary of the first subframe is less than Y2, determining that a
time length of a second signal is Z2, where the second signal
includes the first signal, Z2 belongs to a length set {L.sub.1',
L.sub.2', . . . L.sub.n'}, an end time position of the second
signal is located in the second subframe of the first cell, and the
second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0053] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the method further includes: if the time
length between the determined reference time point and the end
boundary of the first subframe is less than Y3, determining that a
time length of a second signal is Z3, where the second signal
includes the first signal, Z3 is less than M2, an end time position
of the second signal is located at the end boundary of the first
subframe, M2 is a preset minimum time length of the second signal,
and Y3 is a time length that is not equal to X2 and not less than
0.
[0054] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the determining a position of a data channel
according to the determined reference time point includes: if a
time length between the determined reference time point and an end
boundary of the first subframe is less than X3, and the time length
between the determined reference time point and the end boundary of
the first subframe is greater than Y4, determining that the
position of the data channel is located in the first subframe,
where X3 and Y4 are time lengths that are not less than 0, and Y4
is not greater than X3.
[0055] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the data channel carries data scheduling
information of a second subframe of the first cell, where the
second subframe is a next subframe adjacent to the first
subframe.
[0056] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, a correspondence exists between the
reference time point and the position of the data channel, each
reference time point corresponds to one index, and each index
corresponds to one position of the data channel.
[0057] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the position of the data channel includes at
least one of the following positions: a position of a control data
channel or a position of a service data channel.
[0058] With reference to the third aspect and the foregoing
implementation manners of the third aspect, in another
implementation manner, the first cell is a cell on an unlicensed
spectrum.
[0059] According to a fourth aspect, a data transmission method is
provided and includes: determining a reference time point, where
the reference time point is located in a first subframe of a first
cell; determining a sending position of a first signal according to
the reference time point, and sending the first signal in the
sending position of the first signal; and determining a position of
a data channel according to the reference time point, and sending,
in the determined position of the data channel, control data and/or
service data carried on the data channel.
[0060] With reference to the fourth aspect, in an implementation
manner, the determining a reference time point includes:
determining the reference time point according to an index of a
symbol closest to a time point at which a spectrum resource of the
first cell is preempted.
[0061] With reference to the fourth aspect and the foregoing
implementation manner of the fourth aspect, in another
implementation manner, the determining a reference time point
includes: determining the reference time point according to an
index of a symbol that is in a second cell and closest to a time
point at which a spectrum resource of the first cell is preempted,
where the second cell and the first cell are deployed on different
spectrum resources.
[0062] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the first signal includes or carries a first
sequence; and the method further includes: determining the first
sequence according to the reference time point.
[0063] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the determining the first sequence according
to the reference time point includes: determining the first
sequence according to a one-to-one correspondence between sequence
information of the first sequence and the reference time point.
[0064] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the determining a position of a data channel
according to the reference time point includes: if a time length
between the reference time point and an end boundary of the first
subframe is not less than X1, determining that the position of the
data channel is located in the first subframe, where X1 is a time
length that is not less than 0.
[0065] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the method further includes: determining
that a time length of a second signal is M1, where the second
signal includes the first signal, and M1 is a minimum time length
of the second signal.
[0066] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the determining a position of a data channel
according to the reference time point includes:
[0067] if a time length between the reference time point and an end
boundary of the first subframe is less than X2, determining that
the position of the data channel is located in a second subframe,
where the second subframe is a next subframe adjacent to the first
subframe; or
[0068] if a time length between the reference time point and an end
boundary of the first subframe is less than X2, determining that
the position of the data channel is located in a third subframe,
where the third subframe is a next subframe that is in the second
cell and adjacent to the first subframe in time, and the second
cell and the first cell are deployed on different spectrum
resources; where
[0069] X2 is a time length that is not less than 0.
[0070] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the method further includes: if the time
length between the reference time point and the end boundary of the
first subframe is not less than Y1, determining that a time length
of a second signal is Z1, where the second signal includes the
first signal, Z1 belongs to a length set {L.sub.1, L.sub.2, . . .
L.sub.n}, and an end time position of the second signal is located
at the end boundary of the first subframe, where n is an integer
that is not less than 1, .A-inverted.i, 1.ltoreq.i<n,
L.sub.i<L.sub.i+1, and Y1 is a time length that is not equal to
X2 and not less than 0.
[0071] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the method further includes: if the time
length between the reference time point and the end boundary of the
first subframe is less than Y2, determining that a time length of a
second signal is Z2, where the second signal includes the first
signal, Z2 belongs to a length set {L.sub.1', L.sub.2', . . .
L.sub.n'}, an end time position of the second signal is located in
the second subframe of the first cell, and the second subframe is
the next subframe adjacent to the first subframe, where n is an
integer that is not less than 1, .A-inverted.i, 1.ltoreq.i<n,
L.sub.i'<L.sub.i+1', and Y2 is a time length that is not equal
to X2 and not less than 0.
[0072] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the method further includes: if the time
length between the reference time point and the end boundary of the
first subframe is less than Y3, determining that a time length of a
second signal is Z3, where the second signal includes the first
signal, Z3 is less than M2, an end time position of the second
signal is located at the end boundary of the first subframe, M2 is
a minimum time length of the second signal, and Y3 is a time length
that is not equal to X2 and not less than 0.
[0073] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the determining a position of a data channel
according to the reference time point includes: if a time length
between the reference time point and an end boundary of the first
subframe is less than X3, and the time length between the reference
time point and the end boundary of the first subframe is greater
than Y4, determining that the position of the data channel is
located in the first subframe, where X3 and Y4 are time lengths
that are not less than 0, and Y4 is not greater than X3.
[0074] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the data channel carries data scheduling
information of a second subframe of the first cell, where the
second subframe is a next subframe adjacent to the first
subframe.
[0075] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, a correspondence exists between the
reference time point and the position of the data channel, each
reference time point corresponds to one index, and each index
corresponds to one position of the data channel.
[0076] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the position of the data channel includes at
least one of the following positions: a position of a control data
channel or a position of a service data channel.
[0077] With reference to the fourth aspect and the foregoing
implementation manners of the fourth aspect, in another
implementation manner, the first cell is a cell on an unlicensed
spectrum.
[0078] In the embodiments of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
BRIEF DESCRIPTION OF DRAWINGS
[0079] To describe the technical solutions in the embodiments of
the present invention more clearly, the following briefly describes
the accompanying drawings required for describing the embodiments
or the prior art. Apparently, the accompanying drawings in the
following description show merely some embodiments of the present
invention, and a person of ordinary skill in the art may still
derive other drawings from these accompanying drawings without
creative efforts.
[0080] FIG. 1 is a schematic diagram of sending a reservation
signal on a preempted unlicensed spectrum resource;
[0081] FIG. 2 is a schematic flowchart of a data transmission
method according to an embodiment of the present invention;
[0082] FIG. 3a and FIG. 3b are schematic diagrams of determining a
sending position of a first signal according to an embodiment of
the present invention;
[0083] FIG. 4a and FIG. 4b are schematic diagrams of signal
positions according to an embodiment of the present invention;
[0084] FIG. 5 is a schematic diagram of a signal position according
to another embodiment of the present invention;
[0085] FIG. 6 is a schematic diagram of a signal position according
to another embodiment of the present invention;
[0086] FIG. 7 is a schematic diagram of a signal position according
to another embodiment of the present invention;
[0087] FIG. 8 is a schematic diagram of a signal position according
to another embodiment of the present invention;
[0088] FIG. 9 is a schematic diagram of a signal position according
to another embodiment of the present invention;
[0089] FIG. 10 is a schematic diagram of a signal position
according to another embodiment of the present invention;
[0090] FIG. 11 is a schematic flowchart of a data transmission
method according to another embodiment of the present
invention;
[0091] FIG. 12 is a schematic block diagram of a data transmission
device according to an embodiment of the present invention;
[0092] FIG. 13 is a schematic block diagram of a data transmission
device according to another embodiment of the present
invention;
[0093] FIG. 14 is a schematic block diagram of a communications
device according to an embodiment of the present invention; and
[0094] FIG. 15 is a schematic block diagram of a communications
device according to another embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0095] The following clearly and completely describes the technical
solutions in the embodiments of the present invention with
reference to the accompanying drawings in the embodiments of the
present invention. Apparently, the described embodiments are some
but not all of the embodiments of the present invention. All other
embodiments obtained by a person of ordinary skill in the art based
on the embodiments of the present invention without creative
efforts shall fall within the protection scope of the present
invention.
[0096] The technical solutions of the present invention may be
applied to various communications systems, such as: a Global System
for Mobile Communications (GSM, Global System of Mobile
communication), a Code Division Multiple Access (CDMA, Code
Division Multiple Access) system, a Wideband Code Division Multiple
Access (WCDMA, Wideband Code Division Multiple Access Wireless), a
general packet radio service (GPRS, General Packet Radio Service),
and a Long Term Evolution (LTE, Long Term Evolution).
[0097] A user equipment (UE, User Equipment), also referred to as a
mobile terminal (Mobile Terminal), a mobile user equipment, and the
like, may communicate with one or more core networks through a
radio access network (for example, RAN, Radio Access Network). The
user equipment may be a mobile terminal, such as a mobile phone
(also referred to as a "cellular" phone) and a computer with a
mobile terminal. For example, the user equipment may be a portable,
pocket-sized, handheld, computer built-in, or in-vehicle mobile
apparatus, which exchanges language and/or data with the radio
access network; or may be a relay (Relay).
[0098] A base station may be a base station (BTS, Base Transceiver
Station) in the GSM or CDMA, may also be a base station (NodeB) in
the WCDMA, and may further be an evolved NodeB (eNB or e-NodeB,
evolutional Node B) in the LTE, which is not limited in the present
invention.
[0099] An application scenario of the embodiments of the present
invention includes that the embodiments are applied to an LTE
system for licensed-assisted access (Licensed-Assisted Access,
LAA), that is, an LAA-LTE system. The LTE system for
licensed-assisted access refers to an LTE system in which a
licensed spectrum and an unlicensed spectrum are used together in a
CA or non-CA manner. Specifically, the licensed spectrum, or a
carrier included in the licensed spectrum, or a cell working on the
licensed spectrum is used as a primary serving cell, and the
unlicensed spectrum, or a carrier included in the unlicensed
spectrum, or a cell working on the unlicensed spectrum is used as a
secondary serving cell. The primary serving cell and the secondary
serving cell may be deployed on a same site, or may not be deployed
on a same site. There is an ideal backhaul path between the two
serving cells.
[0100] However, the embodiments of the present invention are also
not limited to the foregoing CA scenario, and may be further
applied to other deployment scenarios, for example, a scenario in
which there is no ideal backhaul path between the two serving cells
(primary serving cell and secondary serving cell). Because of a
great backhaul delay, it is possible that information cannot be
quickly coordinated between the two serving cells.
[0101] In addition, independent deployment of the serving cell
working on the unlicensed spectrum may also be considered. That is,
the serving cell working on the unlicensed spectrum may directly
provide an independent access function, and does not require
assistance from the cell working on the licensed spectrum.
[0102] In the embodiments of the present invention, both the
licensed spectrum and the unlicensed spectrum may include one or
more carriers. Carrier aggregation is performed on the licensed
spectrum and the unlicensed spectrum. This may include performing
carrier aggregation on one or more carriers included in the
licensed spectrum and one or more carriers included in the
unlicensed spectrum.
[0103] The cell mentioned in the embodiments of the present
invention may be a cell corresponding to a base station. For
example, the cell may belong to a macro base station, or may belong
to a base station corresponding to a small cell (small cell). Small
cells herein may include a metro cell (Metro cell), a micro cell
(Micro cell), a pico cell (Pico cell), a femto cell (Femto cell),
and the like. These small cells have features of small coverage and
low transmit power, and are used to provide a high-speed data
transmission service.
[0104] In the embodiments of the present invention, concepts of a
carrier and a cell in the LTE system are basically equivalent. For
example, for UE, accessing a carrier is equivalent to accessing a
cell. In the specification of the embodiments of the present
invention, the concept of the cell is uniformly used for
description.
[0105] According to an international spectrum white paper recently
published by the Federal Communications Commission (Federal
Communications Commission, FCC), unauthorized or unlicensed
spectrum resources are more than authorized or licensed spectrum
resources. Currently, a main technology used on the unlicensed
spectrum is WiFi. However, WiFi is disadvantageous in terms of
mobility, security, quality of service (Quality of Service, QoS),
and simultaneous processing of multi-user scheduling. Therefore,
applying LTE devices on the unlicensed spectrum may not only use
the unlicensed spectrum resources efficiently, but also provide
more effective radio access and meet growing requirements for
mobile broadband services. In a future mobile communication
scenario, an LTE device and a WiFi device simultaneously exist on
the unlicensed spectrum. In order that the LTE device can maintain
its advantages over WiFi in terms of mobility, security, quality of
service, and simultaneous processing of multi-user scheduling even
if the LTE device works on the unlicensed spectrum, one method is
to aggregate the licensed spectrum and the unlicensed spectrum in
the carrier aggregation (Carrier Aggregation, CA) manner. That is,
in the CA manner, the LTE device may use the licensed spectrum as a
primary component carrier (Primary Component Carrier, PCC) or a
primary cell (Primary Cell, PCell), and use the unlicensed spectrum
as a secondary component carrier (Secondary Component Carrier, SCC)
or a secondary cell (Secondary Cell, SCell). In this way, the LTE
device can use the licensed spectrum to inherit the conventional
advantages of the LTE device used in wireless communication, for
example, the advantages in terms of mobility, security, quality of
service, and simultaneous processing of multi-user scheduling, and
can also use the spectrum resources on the unlicensed spectrum.
[0106] There is no constraint on use of an unlicensed spectrum by a
wireless communications system and an operator, that is, there is a
case in which multiple operators of multiple communications systems
all want to occupy a same spectrum. Therefore, to achieve fairness
of spectrum usage by different wireless communications systems on
the unlicensed spectrum, in some regions, wireless communications
devices need to comply with specific regulations and rules when
using the unlicensed spectrum. For example, in ETSI EN 301 893
published by the European Telecommunications Standards Institute
(European Telecommunications Standards Institute, ETSI), rules such
as listen before talk (Listen Before Talk, LBT) and channel
bandwidth occupancy requirements are specified for using the
unlicensed spectrum. As specified in ETSI EN 301 893, a wireless
communications device needs to use the LBT rule before occupying an
unlicensed spectrum for communication, that is, before using a
channel, the device first needs to monitor whether the channel is
idle or available. If the channel is available, the unlicensed
spectrum resource may be used for data transmission, but a time of
occupying the channel is limited. After the time of occupying the
channel reaches a maximum limit, the device must release the
unlicensed spectrum for a period of time, that is, data
transmission on the unlicensed spectrum must be stopped for a
period of time. Before using an unlicensed spectrum resource for
data transmission next time, the device must monitor again whether
the channel is available. The device may perform a clear channel
assessment (Clear Channel Assessment, CCA) by performing energy
detection, and determine whether the monitored channel is idle or
available. As currently specified in ETSI EN 301 893, when using
the unlicensed spectrum, the wireless communications device needs
to meet a listen before talk mechanism requirement of frame based
equipment (Frame Based Equipment, FBE) or listen before talk
mechanism requirement of load based equipment (Load Based
Equipment, LBE).
[0107] Therefore, in some regions such as Europe, if an LTE device
wants to use the unlicensed spectrum to perform data communication,
the LTE device needs to comply with the LBT rule. That is, the LTE
device first needs to perform a CCA before using the unlicensed
spectrum, and can send data only after determining that an
unlicensed spectrum resource is available. On the other hand, to
have more opportunities to preempt a spectrum resource, the LTE
device may initiate listening at any time, and this is also allowed
by the regulations and rules. That is, on the unlicensed spectrum,
a time point at which the spectrum resource is available, which is
determined by the LTE device, is also any time. In particular, the
LTE device uses the LBT mechanism of the LBE. Correspondingly,
because the LTE device can send the data after determining that the
unlicensed spectrum resource is available (determining that the
unlicensed spectrum resource is available, while meeting
constraints of regulations), a time point at which the LTE device
sends the data on the unlicensed spectrum is also any time. The LTE
device may detect, in a manner of energy detection, whether an
unlicensed spectrum resource is available. If the LTE device
determines, by performing energy detection in a specified time
range, that received energy is less than a particular threshold,
the LTE device may determine that the unlicensed spectrum resource
is available. On the other hand, the LTE device may also determine,
in a manner of signal parsing, whether an unlicensed spectrum
resource on a channel is available, for example, by detecting a
signal that indicates that the unlicensed spectrum resource is
occupied, or by detecting a network allocation vector (Network
Allocation Vector, NAV). Herein, the NAV indicates a time of
occupying the unlicensed spectrum by a device that occupies the
unlicensed spectrum. Once another device detects the NAV, if the
another device is not a target device served by the device that
sends the NAV, the another device cannot send, in a time range
indicated by the NAV, data on the unlicensed spectrum occupied by
the device that sends the NAV. In addition, the LTE device may
further determine, in the manner of energy detection and/or signal
parsing, whether the unlicensed spectrum resource is available.
[0108] However, for the LTE system, because a determined time point
at which an unlicensed spectrum resource is available is any time,
a start time point for sending data is also any time. However,
currently, data sending and receiving by an LTE device are both
based on a subframe boundary. In this case, how to ensure normal
data communication between LTE devices is a problem that needs to
be considered for the LTE devices working on the unlicensed
spectrum.
[0109] One manner does not require synchronization between the
unlicensed spectrum and a reference time source. In this case, once
an LTE device, for example, an LTE base station, seizes a usage
opportunity on the unlicensed spectrum, the LTE device uses a time
point at which the usage opportunity is currently seized as a
subframe boundary, and performs data communication with another LTE
device, for example, LTE UE. That is, in this case, time
synchronization information on the unlicensed spectrum may be
inconsistent with that provided by the reference time source. For
example, a subframe boundary of the unlicensed spectrum is not
aligned with a subframe boundary of the licensed spectrum, or time
information on the unlicensed spectrum and the licensed spectrum
may be asynchronous. Herein the reference time source may be a
licensed spectrum aggregated with an unlicensed spectrum by CA
aggregation, or a global positioning system (Global Positioning
System, GPS), or a wired network clock synchronization protocol,
for example, the IEEE 1588 protocol, or a synchronization source
base station in radio-interface based synchronization
(Radio-interface based synchronization, RIBS), and the
synchronization source base station is a base station that may
provide a synchronization signal for another base station. Using a
reference time source that is a licensed spectrum aggregated with
an unlicensed spectrum by CA aggregation as an example, in the
embodiments of the present invention, that time information on the
unlicensed spectrum and the licensed spectrum is asynchronous may
include: a time unit boundary of the unlicensed spectrum and a time
unit boundary of the licensed spectrum are not aligned or there is
no fixed offset. Herein the time unit boundary may include an
orthogonal frequency division multiplexing (Orthogonal Frequency
Division Multiplexing, OFDM) symbol boundary, a timeslot (Slot)
boundary, a subframe (Subframe) boundary, a radio frame (Radio
Frame) boundary, a super frame (Super Frame) boundary, or the
like.
[0110] However, a time position for data transmission on the
unlicensed spectrum is determined according to an opportunity
seized by the LTE device to use an unlicensed spectrum resource,
and therefore is random. If time information of the unlicensed
spectrum and time information provided by the reference time source
are asynchronous, additional complexity is caused to a user in
setting the time information of the unlicensed spectrum, and the
asynchronization is disadvantageous to implementing some beneficial
technologies on the unlicensed spectrum, for example, fast
discovery, an enhanced multi-broadcast multi-service (Enhanced
Multi-broadcast Multi-service, eMBMS), and an advanced receiver
(Advanced Receiver).
[0111] Another manner is to keep synchronization between the
unlicensed spectrum and a reference time source. In this case, a
subframe boundary of the unlicensed spectrum may be determined
according to time information provided by the reference time
source. Herein the reference time source is the same as above, and
is not described again herein. After an LTE device (for example, an
LTE base station) seizes an opportunity to use the unlicensed
spectrum, before a next subframe boundary arrives, the LTE device
sends a reservation signal (padding), where the reservation signal
indicates that the LTE device starts to perform data communication
in a next subframe with another LTE device, for example, LTE user
equipment (User Equipment, UE). Herein the data communication may
include control data and service data communication.
[0112] FIG. 1 is a schematic diagram of sending a reservation
signal (padding) on a preempted unlicensed spectrum resource.
[0113] A description is made by using that an LTE device sends a
padding as an example. It is assumed that the LTE device already
performs data communication on a licensed spectrum. As shown by an
upper side of FIG. 1, it is assumed that a subframe with a time
length of 1 ms is used as a transmission unit for data
communication on the licensed spectrum.
[0114] A lower side of FIG. 1 indicates a signal transmission
process on an unlicensed spectrum. For ease of comparison, absolute
time coordinates of signals on the two spectrums on the upper side
and lower side in FIG. 1 are synchronous. In the embodiments of the
present invention, using a reference time source that is a licensed
spectrum aggregated with an unlicensed spectrum by CA aggregation
as an example, "synchronization" between different spectrums means
that subframe boundaries of different spectrums are aligned or that
there is a fixed offset.
[0115] In FIG. 1, a backoff (backoff) phase on the unlicensed
spectrum indicates that the LTE device performs a CCA in the range,
and determines, by performing energy detection and/or signal
parsing, whether the currently detected unlicensed spectrum is
available. If the currently detected unlicensed spectrum is
available, the LTE device sends a reservation signal starting from
determining successful preemption of a channel to arrival of a next
subframe boundary. Herein the subframe boundary may indicate a
start position of data channel transmission that can be detected by
UE, or a start position of a control data channel that can be
detected by UE. An advantage of this practice is that, after the
LTE device, for example, an LTE base station, seizes an opportunity
to use the unlicensed spectrum, and before the LTE base station
transmits data to the UE, the LTE base station may further preempt
the unlicensed spectrum, and may align time information of the
unlicensed spectrum with the reference time source, for example,
align the time information with a subframe boundary of the licensed
spectrum. In this way, the LTE base station may use content carried
by a control channel of the licensed spectrum to indicate a
transmission format of a data channel of the unlicensed spectrum,
and therefore, a quantity of blind detection of the UE may be
reduced. Herein the blind detection includes detecting whether data
channel transmission on the unlicensed spectrum starts.
[0116] Further, herein the subframe boundary may also be other time
units, for example, a time unit that is used for data transmission
and can be identified by the LTE device, for example, one OFDM
symbol, a fractional OFDM symbol, and other time units that can be
supported in the LTE system, for example, a reciprocal of a
sampling rate in the LTE system.
[0117] In summary, the LTE base station may send a padding starting
from seizing an opportunity to use an unlicensed spectrum to
arrival of a next subframe boundary at which data can be
scheduled.
[0118] If a padding is sent, the padding may indicate only that the
LTE device seizes an opportunity to use the unlicensed spectrum,
and does not carry a signal and/or a channel related to data
scheduling, for example, a spectrum identifier of the unlicensed
spectrum, an identity of a cell that uses an unlicensed spectrum
resource to perform data transmission, a physical downlink control
channel (Physical Downlink Control Channel, PDCCH), a physical
control format indicator channel (Physical Control Format Indicator
Channel, PCFICH), a physical hybrid automatic repeat indicator
channel (Physical Hybrid ARQ Indicator Channel, PHICH), a physical
broadcast channel (Physical Broadcast Channel, PBCH), a physical
downlink shared channel (Physical Downlink Shared Channel, PDSCH),
an enhanced physical downlink control channel (Enhanced Physical
Downlink Control Channel, EPDCCH), a physical multicast channel
(Physical Multicast Channel, PMCH), or a reference signal such as a
primary synchronization signal (Primary Synchronization Signal,
PSS), a secondary synchronization signal (Secondary Synchronization
Signal, SSS), a cell-specific reference signal (Cell-specific
Reference Signal, CRS), a UE-specific reference signal (UE-specific
Reference Signal) used for PDSCH data demodulation, a demodulation
reference signal (DeModulation Reference Signal, DM-RS) used for
EPDCCH demodulation, a positioning reference signal (Positioning
Reference Signal, PRS), a channel state information reference
signal (Channel State Information Reference Signal, CSI-RS), or a
discovery reference signal (Discovery Reference Signal, DRS).
Alternatively, the padding may carry the foregoing signal and/or
channel. However, another LTE device (for example, LTE UE) served
by the LTE device sending the padding does not demodulate or
receive the signal and/or channel carried by the padding. That is,
one of features of the padding is that regardless of specific
content carried by the signal, the another LTE device served by the
LTE device sending the signal does not need to demodulate the
signal, or further, the another LTE device served by the LTE device
sending the signal may not receive the signal, and the signal that
meets this feature may be referred to as a reservation signal.
After sending the reservation signal is ended, the base station and
the UE start to perform data communication. In this manner, because
data communication between the base station and the UE starts from
a next subframe, synchronization between the unlicensed spectrum
and the reference time source (for example, the licensed spectrum)
may be implemented.
[0119] However, because a purpose of the padding signal is only to
occupy a channel but not to make a substantive contribution to data
transmission, in a time period for sending the padding signal, an
unlicensed spectrum resource that is already preempted is wasted,
and resource utilization is reduced.
[0120] In addition, the foregoing solution does not consider
adverse impact of a time position in which the backoff phase is
ended on a position of the data channel. In other words, no matter
in which position of the subframe the backoff phase is ended, the
data channel starts to be transmitted from a start position of the
next subframe. This also causes waste of an unlicensed spectrum
resource.
[0121] Using the case in FIG. 1 as an example, if a time position
in which the backoff phase is ended is just after a start time
position of a subframe of a licensed spectrum resource, almost
unlicensed spectrum resources of one subframe can be used only for
sending a padding signal, and consequently, unlicensed spectrum
resources with a length of one subframe are wasted.
[0122] FIG. 2 is a schematic flowchart of a data transmission
method according to an embodiment of the present invention. The
method in FIG. 2 is performed by a receive end (for example, an LTE
device, such as an LTE base station or UE).
[0123] 201. Detect a first signal in a first cell.
[0124] 202. Determine a reference time point according to a first
sequence of the detected first signal, where the reference time
point is located in a first subframe of the first cell.
[0125] 203. Determine a position of a data channel according to the
determined reference time point, where the data channel is used to
carry control data and/or service data.
[0126] 204. Receive the data channel according to the position of
the data channel.
[0127] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
[0128] Specifically, in this embodiment of the present invention, a
receive end detects a first signal sent on an unlicensed spectrum,
determines a reference time point according to a first sequence of
the detected first signal, and then determines a receiving position
of a data channel according to a position of the reference time
point in a subframe. In this way, a detection signal and a data
channel are sent on a preempted unlicensed spectrum resource, the
preempted unlicensed spectrum resource can be fully used, and
resource utilization is improved.
[0129] It should be noted that, similar attributes such as "first",
"second", and "third" before terms in the specification of the
present invention are not used to limit a sequence of the terms,
but used only for distinguishing. For example, "first signal" and
"second signal" mean that the two signals may represent different
signal carriers. In other words, the two signals may also represent
a same signal carrier, but anyway, the two signals do not mean that
the first signal is located before the second signal in time. If a
sequence relationship exists definitely, it is particularly pointed
out in the specification of the present invention.
[0130] The first cell may be a cell on the unlicensed spectrum. The
first signal may be used to indicate that a transmit end has
preempted a spectrum resource of the first cell on the unlicensed
spectrum. A preemption operation in this embodiment of the present
invention may include a preemption operation performed according to
a backoff process in FIG. 1, or may include preemption operations
in other forms, for example, an unlicensed spectrum resource
pattern (pattern) preset according to a protocol specification. For
example, the first signal may indicate, to the receive end in an
explicit or implicit manner, that the transmit end has preempted a
spectrum resource on the unlicensed spectrum. In an embodiment, the
explicit manner may be that the first signal may carry a specific
flag (flag) field or a similar indication field, and different flag
values indicate whether an unlicensed spectrum resource is
preempted. In another embodiment, the implicit manner may be that
sending the first signal or not is used to indicate whether the
transmit end has preempted an unlicensed spectrum resource. For
example, an action of sending the first signal indicates that the
transmit end has preempted an unlicensed spectrum resource. In
addition, the first signal may be used for other purposes, for
example, used for synchronizing or transmitting other useful
information.
[0131] The first cell in this embodiment of the present invention
may be a cell deployed on the unlicensed spectrum. One of functions
of the first signal is that the receive end determines, by
detecting the first signal, whether the first cell that sends the
first signal has data transmission on the spectrum on which the
first cell is deployed. For example, when the first cell is
deployed on the unlicensed spectrum, the receive end may determine,
by detecting the first signal, whether the first cell starts to use
the unlicensed spectrum or whether the first cell seizes an
opportunity to use a spectrum resource on the unlicensed spectrum.
The first signal may be a reference signal, for example, may be one
of the following reference signals: a PSS, an SSS, a CRS, a CSI-RS,
a PRS, a DRS, a DMRS, or a UE specific reference signal used for
PDSCH demodulation. In another embodiment, the first signal in this
embodiment of the present invention may also be a channel carrying
data, for example, one of the following channels: a PDCCH, a PDSCH,
an EPDCCH, a PMCH, a PBCH, a PCFICH, a PHICH, or the like.
[0132] The first signal includes or carries the first sequence. For
example, the first sequence has N different sequence forms, and no
matter which sequence form is used for the first sequence, the
first sequence may be included in the first signal. UE may
determine, by detecting the first signal, the sequence form of the
first sequence included in the first signal, and this may be
referred to as the first sequence of the detected first signal.
More specifically, for example, a PSS in an existing LTE system is
used as the first signal; in this case, the first sequence may be
Zadoff-Chu sequences forming the PSS; and the UE may determine, by
detecting the PSS, which Zadoff-Chu sequence, namely, which first
sequence, is carried in the detected PSS. For another example, an
SSS in the existing LTE system is used as the first signal; in this
case, the first sequence may be 168 sequences forming the SSS, and
any one in the 168 sequences is a combination of two binary
sequences having a length of 31. In addition, that the first signal
includes the first sequence may also be that a part of the first
signal includes the first sequence. For example, the first signal
occupies multiple time units (for example, A OFDM symbols) in time,
and a signal carrying the first sequence is a part of the first
signal, that is, from a time perspective, occupies a part of
multiple time units occupied by the first signal in time (for
example, B OFDM symbols, where B is less than or equal to A, and
time positions corresponding to the B OFDM symbols are a non-null
subset of time positions corresponding to the A OFDM symbols). In
addition, the first signal may also be a channel including or
carrying the first sequence. In this embodiment of the present
invention, the term signal or channel may indicate a carrier that
is used to carry specific information or data and occupies a
specific time-frequency resource.
[0133] The data channel may be independent of the first signal, for
example, sent after the first signal. The data channel and the
first signal may also occupy a same time resource, for example, are
multiplexed on the time resource in orthogonal mode such as
frequency division, space division, or code division. A time
resource occupied by the first signal may also be a part of a time
resource occupied by the data channel. For example, a time resource
occupied by the data channel is three OFDM symbols, and
specifically, a third OFDM symbol to a fifth OFDM symbol in a
subframe. In this case, the time resource occupied by the first
signal may be any one or more of the three OFDM symbols. The data
channel may be used to carry control data and/or service data. An
example of the control data includes but is not limited to data
carried by a PDCCH, an EPDCCH, a PBCH, a PHICH, or a PCFICH. An
example of the service data includes but is not limited to data
carried by a PDSCH or a PMCH. In addition, in this embodiment of
the present invention, a detection operation of the receive end on
the first signal may be real-time blind detection, for example,
detecting whether the first signal exists during signal reception,
or may be first buffering the first signal and then detecting the
first signal.
[0134] In the following embodiment, for ease of description, a case
in which the transmit end is an LTE base station and the receive
end is LTE UE is mainly used as an example for description, that
is, a case in which the first signal and the data channel are a
downlink signal and channel is used as an example for description.
A person skilled in the art easily understands that a case in which
the first signal and the data channel are an uplink signal and
channel may be designed or modified similarly. Such a design or
modification still falls within the scope of this embodiment of the
present invention.
[0135] To implement data communication between the first cell and
the UE on the unlicensed spectrum, once the first cell seizes an
opportunity to use the unlicensed spectrum, before performing
control data and/or service data transmission with the UE, the
first cell may first send other control information used for
detecting control data and/or service data, or before the UE
demodulates control data and/or service data communication, the UE
needs to first learn other control information used for detecting
control data and/or service data. For example, the other control
information may include information that enables the UE to
determine that the first cell seizes an opportunity to use the
unlicensed spectrum, a cell identity of the first cell,
synchronization information of the first cell, a public land mobile
network (Public Lands Mobile Network, PLMN) identifier of the first
cell, or more generally, necessary control information supporting
data transmission (including control data transmission and/or
service data transmission) in the current LTE system, for example,
information carried on a PBCH or information carried in a system
information block (System Information Block, SIB). The other
control information may be carried in a signal and/or a channel.
For example, the synchronization information of the first cell may
be carried by a synchronization signal sent by the first cell. In
this embodiment of the present invention, a carrier carrying the
other control information is referred to as a second signal, or may
be referred to as a second channel. For example, the second signal
may be in a form of a preamble (preamble), and the preamble carries
the other control information. However, the form or a specific name
of the second signal is not limited in this embodiment of the
present invention. In this embodiment of the present invention, the
term "signal" is mainly used for description. However, this may
also be extended to a case in which the term "channel" is used, and
the extension falls within the scope of this embodiment of the
present invention. The second signal sent by the first cell may
occupy multiple time units in time. Herein the time unit may be a
length of one OFDM symbol, or may occupy a length of a fractional
OFDM symbol, or may be another length representation form related
to a length of an OFDM symbol, for example, a reciprocal Ts of a
sampling rate, where 15360*Ts=0.5 milliseconds, or more generally,
may be an integer multiple of a time unit that can be identified by
the LTE system. To implement normal data communication between the
first cell and the UE on the unlicensed spectrum, from a
perspective of a synchronization requirement meeting normal data
communication, the second signal may occupy X OFDM symbols in time,
where X may be any positive integer. For example, assuming that X
is set to 4 to implement a requirement of frequency synchronization
between the first cell and the UE on the unlicensed spectrum, a
signal carried by a first OFDM symbol may enable the UE to learn
whether the first cell has seized an opportunity to use a spectrum
resource on the unlicensed spectrum. In this case, the UE may
learn, by detecting energy of the first OFDM symbol or parsing
(demodulating) the signal carried by the first OFDM, whether the
first cell has seized an opportunity to use a spectrum resource on
the unlicensed spectrum. Certainly, the time length occupied by the
second signal in time may be determined according to a met function
provided by the second signal.
[0136] The first signal may be a part of the second signal, or may
be just the second signal. For example, the first signal may
include only the first OFDM symbol of the second signal in time.
The UE may determine, by detecting the first signal, whether the
first cell has seized an opportunity to use a spectrum resource on
the unlicensed spectrum.
[0137] Correspondingly, the reference time point and a length of
the second signal are then determined according to the first
sequence of the detected first signal. For another example, the
first signal is just the second signal. The first sequence of the
detected first signal may include a detected signal carrying the
first sequence, where the signal carrying the first sequence is a
part of the first signal.
[0138] The determining a reference time point according to the
first sequence of the detected first signal may specifically
include at least one of the following manners: determining the
reference time point according to a time position of the signal
carrying the first sequence; determining the reference time point
according to a time position of the signal carrying the first
sequence and a correspondence between the signal carrying the first
sequence and a time position of the first signal; or determining
the reference time point according to a time position of the signal
carrying the first sequence and a relative time relationship
between the signal carrying the first sequence and the reference
time point. The following uses specific embodiments for
description.
[0139] Optionally, in an embodiment, the determining a reference
time point according to the detected first sequence in step 202 may
be: determining the reference time point according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0140] In other words, a one-to-one correspondence may exist
between the sequence information of the first sequence and the
reference time point (for example, in a form of a table). This
helps to determine the corresponding reference time point according
to the sequence information of the detected first sequence.
[0141] The first sequence is designed to indicate the reference
time point of the first cell on the unlicensed spectrum. As
described above, the reference time point may be indicated by a
position of an OFDM symbol, or may be indicated by a position of a
fractional OFDM symbol, or more generally, indicated by an integer
multiple of Ts, or indicated by an integer multiple of a time unit
that can be identified by the LTE system.
[0142] In an embodiment of the present invention, assuming that
reference time points are different OFDM symbol positions included
in a subframe, different OFDM symbol positions may be indicated by
different OFDM symbol indexes. For example, a correspondence
between an OFDM symbol position and an OFDM symbol index may be
shown in the following Table 1, where the symbol index is an
example of the sequence information.
TABLE-US-00001 TABLE 1 Example of a correspondence between symbol
index and symbol position in a subframe A subframe Symbol index 0 1
2 3 4 5 6 7 8 9 10 11 12 13 Symbol First Second Third Fourth Fifth
Sixth Seventh Eighth Ninth Tenth Eleventh Twelfth Thirteenth
Fourteenth position symbol symbol symbol symbol symbol symbol
symbol symbol symbol symbol symbol symbol symbol symbol
[0143] In another embodiment of the present invention, the
reference time point may be indicated by a position of a fractional
OFDM symbol. A position of a fractional OFDM symbol (for example, a
position of a 1/4 OFDM symbol) may be determined jointly according
to an index of an OFDM symbol and a position (or an index) of the
fractional OFDM symbol in the OFDM symbol, or may be determined
according to positions (or indexes) of all fractional OFDM symbols
sorted in a time unit, where the time unit may be a subframe, a
timeslot, a radio frame, or another time unit that can be
identified by another LTE UE, for example, an integer multiple of a
reciprocal Ts of a sampling rate.
[0144] Specifically, the following describes a case in which a
reference time point is indicated by a position of an OFDM symbol.
According to Table 1, a reference time point in a subframe has a
maximum of 14 states. Then a maximum of 14 different first
sequences may be used for indication. Once the first cell preempts
a spectrum resource on the unlicensed spectrum, the first cell may
determine the reference time point according to a relationship
between a time position of the preempted spectrum resource on the
unlicensed spectrum and a time position of a reference time source,
and then may determine a start sending position of the first signal
according to the reference time point, for example, use the
determined reference time point as the start sending position of
the first signal. At the same time, the first cell determines the
first sequence according to the one-to-one correspondence between
the reference time point and the sequence information of the first
sequence, and adds the first sequence to the first signal for
sending.
[0145] FIG. 3a and FIG. 3b are schematic diagrams of determining
the sending position of the first signal according to an embodiment
of the present invention.
[0146] In examples of FIG. 3a and FIG. 3b, it is assumed that the
reference time source comes from a second cell, where the second
cell is a cell aggregated with the first cell by CA aggregation.
The second cell and the first cell may be deployed on a same base
station, or may be deployed on different base stations. In
addition, subframe boundaries of the second cell and the first cell
are aligned, or there is a slight time difference, for example, 260
nanoseconds. In this way, the second cell may determine a symbol
position of the second cell according to a symbol position of the
first cell.
[0147] If a time point at which the first cell successfully seizes
an opportunity to use a spectrum resource on the unlicensed
spectrum is a boundary of an OFDM symbol, as shown in FIG. 3a, for
example, the first cell determines, at an end boundary of a fourth
OFDM symbol, that a spectrum resource on the unlicensed spectrum
may be used, the first cell may determine that the start sending
position of the first signal is located at a start boundary of a
fifth OFDM symbol, or that transmission of a first symbol of the
first signal in time may start from a fifth OFDM symbol.
[0148] If a time point at which the first cell successfully seizes
an opportunity to use a spectrum resource on the unlicensed
spectrum is not a boundary of an OFDM symbol, as shown in FIG. 3b,
the first cell sends a padding (reservation signal) before the
fifth OFDM symbol starts to send the first signal and after the
spectrum resource on the unlicensed spectrum is successfully
preempted, where the reservation signal may be a part of the first
signal. In an extended sense, if a time point at which the first
cell successfully seizes an opportunity to use a spectrum resource
on the unlicensed spectrum may be indicated by a time supported by
the system, for example, an integer quantity of OFDM symbol
boundaries, or a fractional OFDM symbol boundary, the first cell
may directly send the first signal after successfully preempting
the unlicensed spectrum; however, if the time point may not be
indicated by a time supported by the system, the first cell may
send a padding before sending the first signal and after
determining that the unlicensed spectrum is available. In the
embodiment in FIG. 3b, although the padding is sent, a time
occupied by the sent padding is very short, and does not exceed a
length of one symbol or one fractional symbol. Therefore, there is
little impact on resource utilization.
[0149] At the transmit end, for example, an LTE base station side,
the first cell determines the reference time point, and then
determines the first sequence according to a one-to-one
correspondence between the reference time point and the first
sequence, and further determines content to be sent in the first
signal. For example, it is assumed that the first signal occupies a
length of one OFDM symbol in time, and that a used signal is a PSS.
In the LTE system, Zadoff-Chu sequences forming a PSS have four
different forms (the current LTE system uses three of the forms).
Therefore, the first sequence of the first signal may have a
maximum of four different sequence forms, and may indicate four
different reference time points.
[0150] In an embodiment of the present invention, in a subframe,
from a perspective of an OFDM symbol index, the reference time
point has 14 different states.
[0151] In another embodiment, if OFDM symbol indexes are
classified, for example, OFDM symbol indexes in a subframe are
classified into four types, it may be considered that there are
four types of reference time points. The first cell may determine
the sequence form of the first sequence according to a
correspondence between the determined reference time points and
sequences forming the PSS, and further determine the content to be
sent in the first signal.
[0152] For another example, the first signal occupies a length of
two OFDM symbols in time, and a signal carried by the first OFDM
symbol is used by the UE to determine that the first cell has
seized an opportunity to use a spectrum resource on the unlicensed
spectrum. For example, the UE may use the PSS, and determine, by
performing energy detection and/or signal parsing on the PSS,
whether the first cell has seized an opportunity to use a spectrum
resource on the unlicensed spectrum. Content sent in a signal (for
example, an SSS) carried by the second OFDM symbol corresponds to
the reference time point one one-to-one basis. That is, the content
sent in the signal carried by the second OFDM symbol is the first
sequence. In this case, although the first sequence is only a part
of the first signal, the UE can also detect the first sequence by
detecting the first signal. In a typical LTE system, sequences
forming an SSS have 168 different sequence forms in total.
Therefore, 14 different sequence forms are selected from the
sequences forming the SSS and may be used to indicate 14 different
reference time points.
[0153] The first cell may determine, according to the determined
reference time point, for example, the start sending position of
the first signal, a sending position of the first sequence included
in the first signal. In this example, the first cell may determine
the reference time point according to a relationship between the
time point at which the first cell seizes the opportunity to use
the unlicensed spectrum and synchronization information of the
second cell. In this example, the sending position of the first
sequence is located in a second OFDM symbol position of the first
signal, and then an appropriate sequence is selected according to a
correspondence between the sending position of the first sequence
and different sequence forms forming the SSS, and is used as
content sent in the signal carried by the second OFDM symbol of the
first signal.
[0154] The first cell may determine its own synchronization
information in other manners, for example, by using the
synchronization information of the first cell, in addition to the
synchronization information of the second cell. The synchronization
information of the first cell may come from a GPS or a wired
network synchronization protocol, or may be obtained by listening
to a synchronization reference signal of another cell.
[0155] In this manner, on a UE side, the UE detects the first
signal according to a time unit that may indicate the reference
time point. As described above, the reference time point may be
indicated by a position of an OFDM symbol, or may be indicated by a
position of a fractional OFDM symbol, or more generally, indicated
by a time unit that may be supported by the LTE system, for
example, an integer multiple of a reciprocal Ts of a sampling rate.
These indication forms may all be considered as positions of the
reference time point in the first subframe.
[0156] For example, a case in which the reference time point is
indicated by a position of an OFDM symbol is described. In one
case, the UE detects, by using all possible sequence forms of the
first sequence, whether the signal of the first cell includes the
first sequence, and if the first sequence is included, further
determines the form of the first sequence, and then determines the
reference time point according to a correspondence between the
sequence form of the first sequence and the reference time point.
Alternatively, the UE may first determine the synchronization
information of the first cell according to the synchronization
information of the second cell, for example, determine the subframe
boundary of the second cell according to the subframe boundary of
the first cell. After determining the subframe boundary of the
first cell, the UE may detect the first signal by using a symbol
length of the first signal in time in a neighborhood of a symbol
position understood by the UE. Herein the neighborhood of the
symbol position may indicate that the UE detects a symbol boundary
of the first cell by detecting the first signal by using a sliding
window method. The UE may perform related detection by using
different possible sequence forms of the first sequence and the
received signal, or use another detection method. For the detected
first sequence, the UE may determine the reference time point
according to the correspondence between the detected first sequence
and the reference time point. For example, if content sent by the
first OFDM symbol of the first signal is the first sequence, the
determined reference time point may be an OFDM symbol position in
which the first sequence is sent; or if content sent by the second
OFDM symbol of the first signal is the first sequence, the
determined reference time point may be an OFDM symbol position in
which the first sequence is sent, or may be the start sending
position of the first signal. The correspondence between the
reference time point and the sequence and whether the reference
time point corresponds to the start sending position of the first
signal or another data sending position may be predefined or
specified in a standard, or may be notified to the UE by using
signaling by any cell included in a base station in which the first
cell is located. If the symbol boundaries of the first cell and the
second cell are also synchronized on the UE side, the UE may
further determine an understanding about the symbol boundary of the
first cell by directly using an understanding about the symbol
boundary of the second cell, so as to detect the first signal at
intervals of one symbol or at intervals of multiple symbols.
Further, the UE may further buffer data with a length in the first
cell, and then perform detection.
[0157] In this embodiment of the present invention, the UE may not
only determine the synchronization information of the first cell
according to the synchronization information of the second cell,
but also determine the synchronization information of the first
cell according to historical synchronization information of the
first cell, that is, for the first cell that works on the
unlicensed spectrum, using an unlicensed spectrum resource is
opportunistic. If the first cell served the UE when obtaining an
unlicensed spectrum resource last time, the UE may determine
current synchronization information of the first cell according to
previous synchronization information of the first cell that served
the UE.
[0158] More generally, in the present invention, the one-to-one
correspondence between the sequence information of the first
sequence and the reference time point may be: the sequence
information of the first sequence is directly used to indicate the
reference time point, or a particular relationship exists between a
time position indicated by the sequence information of the first
sequence and the reference time point, for example, at intervals of
several OFDM symbols or at intervals of several fractional OFDM
symbols. Therefore, the reference time point may be determined by
using the time position indicated by the first sequence and the
relationship between the time position indicated by the sequence
information of the first sequence and the reference time point. It
should be noted that, in this embodiment of the present invention,
sequence information of one first sequence may indicate multiple
different reference time points, or may indicate one reference time
point; on the other hand, sequence information of multiple
different first sequences may indicate one reference time point, or
may indicate multiple different reference time points.
[0159] One understanding about the one-to-one correspondence
between the sequence information of the first sequence and the
reference time is that, the sequence information of the first
sequence indicates a time position of a signal carrying the first
sequence, where the signal carrying the first sequence is a part of
the first signal. If the reference time point is defined as a start
time position of the first signal, the one-to-one correspondence
between the sequence information of the first sequence and the
reference time point may be understood as follows: the time
position of the signal carrying the first sequence is first
determined according to the sequence information of the first
sequence, and then the start time position of the first signal is
determined according to the position of the signal carrying the
first sequence in the first signal, that is, the reference time
point is determined. Specifically, for example, the first signal
occupies two OFDM symbols in time, and the time position of the
signal carrying the first sequence in the first signal is two OFDM
symbols. Assuming that it is determined, according to the sequence
information of the first sequence, that the signal carrying the
first sequence is located in a C.sup.th OFDM symbol, it may be
learned that the start position of the first signal is located in a
(C-1).sup.th OFDM symbol. Alternatively, if the time position of
the signal carrying the first sequence in the first signal is the
start time position of the first signal, that is, if the time
position of the signal carrying the first sequence in the first
signal is the first OFDM symbol, the start time position of the
first signal may be determined directly according to the sequence
information of the first sequence. For symbol positions and symbol
indexes in a subframe, reference may be made to Table 1.
[0160] Another understanding about the one-to-one correspondence
between the sequence information of the first sequence and the
reference time point is that, if the reference time point is the
start time position of the first signal, no matter where the
position of signal carrying the first sequence in the first signal
is, the sequence form of the first sequence is used to indicate the
start time position of the first signal, that is, the reference
time point is directly indicated.
[0161] In this embodiment of the present invention, in addition to
the assumption that the reference time point is the start time
position (the start position may be indicated by an OFDM symbol
index) of the first signal in the foregoing description of the
embodiment, the reference time point may also be another time
position of the first signal, for example, an end time position of
the first signal, or one or more positions of the first signal from
the start time position to the end time position. For example,
assuming that the first signal occupies W OFDM symbols in time, and
that positions of the W OFDM symbols in a subframe may be indicated
by OFDM symbol indexes, for example, #w, #(w+1), . . . , #(w+W-1),
the reference time point may be indicated by any one or more values
in an OFDM symbol index set {#w, #(w+1), . . . , #(w+W-1)}. In
addition to being indicated by a symbol index, the time position of
the first signal may have other forms, for example, using a
fractional OFDM symbol as a unit, such as using a 1/Z OFDM symbol
as a unit, where Z is preferentially a positive integer.
Correspondingly, the reference time point may also be indicated by
an OFDM symbol position or index using a fractional symbol as a
unit, for example, a first (1/Z).sup.th OFDM symbol or a second
(1/Z).sup.th OFDM symbol. Alternatively, the time position of the
first signal may be indicated by using a time that can be
identified by a cell and/or user equipment UE in the LTE system as
a unit, for example, a reciprocal Ts of a sampling rate. In this
case, the time position of the first signal may be indicated by an
integer quantity of Ts. Further, the reference time point may also
be any one or more time points in the first subframe of the first
cell, and may be indicated by an absolute time, or may be indicated
by a relative time in the first subframe, for example, an OFDM
symbol or a timeslot; or may be indicated by a relative time in a
long time (one or an integer quantity of radio frames, or one radio
super frame), for example, located in an OFDM symbol, a timeslot,
or a subframe in the long time range. In this case, as described
above, as long as the one-to-one correspondence between the
sequence information of the first sequence and the reference time
point is known, no matter whether the time point indicated by the
sequence information of the first sequence is the reference time
point or a specific time relationship exists between the time point
indicated by the sequence information of the first sequence and the
reference time point, the reference time point may be determined
according to the detected sequence information of the first
sequence. The sequence information of the first sequence may
include one or more of a time resource, a frequency resource, or a
code resource carrying the first sequence. Different forms and/or
different combinations of one or more of a time resource, a
frequency resource, or a code resource of the first sequence may
correspond to reference time points on a one-to-one basis. The time
resource of the first sequence may include an OFDM symbol, a
timeslot, a subframe, a radio frame, or the like that carries the
first sequence. On the other hand, if the signal carrying the first
sequence occupies one OFDM symbol in time, when the time resource
of the first sequence is a timeslot, a subframe, or a radio frame,
the time resource of the first sequence may further be the
timeslot, the subframe, or the radio frame including the signal
carrying the first sequence; further, the time resource carrying
the first sequence may also be a fractional OFDM symbol. The
frequency resource of the first sequence may include a frequency
resource occupied by the signal carrying the first sequence, for
example, may be indicated by a subcarrier, a resource element
(Resource Element, RE), a resource block (Resource Block, RB), a
physical resource block (Physical Resource Block, PRB), or a
virtual resource block (Virtual Resource Block, VRB). The code
resource of the first sequence may include sequences used for
forming the first sequence. For example, if the sequences used for
forming the first sequence are sequences forming the PSS in the
current LTE system, the code resource of the first sequence
includes one or more of three Zadeoff-Chu (ZC) sequences. In this
case, one sequence (ZC1) in the Zadeoff-Chu sequences may be used
to correspond to one reference time point, and another sequence
(ZC2) in the Zadeoff-Chu sequences is used to correspond to another
reference time point, and so on. For another example, if the
sequences used for forming the first sequence are sequences forming
the SSS in the current LTE system, the code resource of the first
sequence is one or more of sequences, namely, m sequences, forming
the SSS. More generally, the code resource of the first sequence
may be sequences used in the current LTE system, for example, ZC
sequences, binary sequences, or m sequences.
[0162] In the foregoing process, both the base station and the UE
may know the one-to-one correspondence between the sequence
information of the first sequence and the reference time point, for
example, the correspondence between the sequence information of the
first sequence and the reference time point, the time position of
the signal carrying the first sequence in the first signal, or the
relationship between the time position indicated by the reference
time point and the time position indicated by the sequence
information of the detected first sequence. For the UE, the
one-to-one correspondence between the sequence information of the
first sequence and the reference time point may be known by the UE
in a manner such as predefinition, standard specification,
signaling notification, or factory setting. For the base station,
the correspondence may be learned by the base station in a manner
such as predefinition, standard specification, signaling
interaction, or factory setting.
[0163] Incidentally, in this embodiment of the present invention,
unless otherwise specified, all content that needs to be learned by
the base station or the UE may be learned in a manner such as
predefinition, standard specification, signaling interaction, or
factory setting, that is, the manner of learning content by the
base station or the UE is not limited in this embodiment of the
present invention.
[0164] Optionally, in another embodiment of the present invention,
when the reference time point is determined according to the
detected first sequence in step 202, the reference time point may
be determined according to an index of a symbol that is in the
first cell and closest to a position of the first sequence.
[0165] In this embodiment of the present invention, symbol indexes
may correspond to relative positions of symbols in a subframe on a
one-to-one basis, as shown in Table 1.
[0166] Using a case in which the first signal and the data signal
are a downlink signal and channel as an example, on the base
station side, the first cell may obtain the synchronization
information of the first cell in a manner such as a GPS or a wired
network synchronization protocol, or obtain the synchronization
information of the first cell by listening to a synchronization
reference signal of another cell in a manner of air-interface
synchronization, and further determine a subframe boundary, a
timeslot boundary, a symbol boundary, a frame boundary, a super
frame boundary of the first cell, or the like. Afterward, the first
cell sends, according to a time point at which the first cell
seizes an opportunity to use an unlicensed spectrum resource, the
first signal starting from a position of an index of a symbol that
is after the time point and closest to the time point, or starting
from a position of an index of a symbol that is after the time
point and has a specific distance from the time point, where the
first signal carries the first sequence, and the specific distance
may be learned by the cell and/or the UE in a manner of
predefinition, standard specification, or signaling interaction.
Herein, if the time point at which the first cell seizes the
opportunity to use the unlicensed spectrum resource is not an end
boundary at which the first cell may send data, for example, a
symbol boundary, the first cell may send a padding starting from
seizing the opportunity to use the unlicensed spectrum resource and
before the first signal starts to be sent.
[0167] According to the synchronization information of the first
cell, the UE obtains time information of the first cell, for
example, a radio frame index, a subframe index, a timeslot index,
and a symbol index of the first cell. The UE may obtain the
foregoing information by tracing a synchronization signal of the
first cell. For example, the UE may obtain the synchronization
information of the first cell by reading a synchronization
reference signal sent by the first cell, for example, a PSS, an
SSS, a CRS, a UE-specific reference signal (UE-specific Reference
Signal) used for PDSCH data demodulation, a demodulation reference
signal DM-RS used for EPDCCH demodulation, a PRS, a CSI-RS, a DRS,
or a multicast broadcast single frequency network reference signal
(Multicast Broadcast Single Frequency Network Reference Signal,
MBSFN RS). Alternatively, considering that data sending is
opportunistic if the first cell works on the unlicensed spectrum,
when the UE determines the reference time point according to the
synchronization information of the first cell, synchronization
information of the first cell that is stored historically may be
further used as synchronization information of the first cell for
determining the reference time point. The UE may determine an OFDM
symbol position in the first cell by using the synchronization
information of the first cell that is stored historically. For
example, the UE may have the synchronization information of the
first cell that is stored historically, but there is a difference
between the synchronization information and actual synchronization
information of the first cell. In this case, the UE may further
determine the time synchronization information of the first cell by
using the detected first sequence, for example, an OFDM symbol
boundary or an OFDM symbol position. In this way, a time position
of the reference time point may be determined accurately (for
example, indicated by an OFDM symbol index or an OFDM symbol
position). The UE may detect the first signal according to the
obtained time information of the first cell. For example, detection
is performed by using an OFDM symbol as a unit. Once the first
sequence is detected, because the UE has obtained the time
information of the first cell, the time position of the signal
carrying the first sequence may be directly learned, and the
position or a variation of the position is used as the reference
time point. Herein the "variation" means that if the reference time
point refers to the start sending position of the first signal, but
the first sequence is not content included in the signal sent by
the first OFDM symbol, after the time position of the detected
first sequence is determined, the reference time point needs to be
determined according to the symbol position of the signal carrying
the first sequence in the first signal.
[0168] As described above, assuming that the reference time point
is indicated by an OFDM symbol position in the first subframe, and
that the time position corresponding to the reference time point is
a time position close to the signal carrying the first sequence,
for example, the time position of the signal carrying the first
sequence in the first subframe is a D.sup.th OFDM symbol in the
first subframe or is indicated by an OFDM symbol whose symbol index
is #(D-1) in the first subframe, the index of the symbol closest to
the position of the first sequence may be a (D-1).sup.th OFDM
symbol, or may be the D.sup.th OFDM symbol, or may be a
(D+1).sup.th OFDM symbol. More generally, the reference time point
may be determined according to an index of a symbol that is in the
first cell and has a specific time relationship with the position
of the first sequence, in addition to the index of the symbol that
is in the first cell and closest to the position of the first
sequence, where the specific time relationship may be indicated by
an integer quantity of OFDM symbol indexes, and may be predefined
or may be learned by the UE in a signaling manner. For example, the
first signal includes multiple OFDM symbols. The reference time
point is the start time position of the first signal, and may be
indicated by a time position of the first OFDM symbol carrying the
first signal, and the signal carrying the first sequence is the
second OFDM symbol in the first signal. In this case, the
determining a reference time point according to the detected first
sequence includes: determining the reference time point according
to the detected first sequence and a relationship between the time
position of the signal carrying the first sequence and the time
position reflected by the reference time point. In this example,
the index of the symbol that is in the first cell and before the
position of the detected first sequence and closest to the position
of the first sequence is used as the reference time point. It
should be noted that, in this embodiment of the present invention,
an OFDM symbol position or an OFDM symbol index is used as an
example to indicate the reference time point, the time position of
the first sequence of the detected first signal, and the time
position of the first signal (including the start time position,
the end time position, and one or more positions from the start
time position to the end time position of the first signal in
time). However, the technology in this embodiment of the present
invention is further applicable to indicating the reference time
point, the time position of the first sequence of the detected
first signal, the time position of the first signal, and the like
by using other time information, for example, a position of a
fractional OFDM symbol or an index of a factional OFDM symbol, or
by using a signal sampling rate and/or a reciprocal of a signal
sampling rate. These implementation manners all fall within the
scope of this embodiment of the present invention.
[0169] In summary, as an extension to this embodiment, the
determining a reference time point according to the detected first
sequence may further include: determining the reference time point
according to an index of a symbol that is in the first cell and
closest to a position of the first sequence, and a relative
position of the signal carrying the first sequence in the first
signal. For example, the reference time point is defined as any
position from the start time position to the end time position of
the first signal. In this case, the index of the symbol that is in
the first cell and closest to the position of the first sequence
may be considered as the time position of the signal carrying the
first sequence, and then any position from the start time position
to the end time position of the first signal, indicated by an OFDM
symbol index, may be determined with reference to the time position
of the signal carrying the first sequence and the relative position
of the signal carrying the first sequence in the first signal, and
the reference time point is further determined. In a further
extended embodiment, the determining a reference time point
according to the detected first sequence may further include:
determining the reference time point according to an index of a
symbol that is in the first cell and closest to a position of the
first sequence, and a relative relationship between the signal
carrying the first sequence and the reference time point. For
example, the reference time point is defined as an E.sup.th OFDM
symbol in the first subframe. According to a fact that the index of
the symbol that is in the first cell and closest to the position of
the first sequence is an F.sup.th OFDM symbol in the first
subframe, a time position of the E.sup.th OFDM symbol in the first
subframe may be determined according to a time position of the
detected F.sup.th OFDM symbol (which may be indicated by a symbol
position) and a relative relationship between E and F (for example,
how many OFDM symbols exist between the two positions), and then
further the time position of the reference time point is
determined, or the reference time point is determined.
[0170] Optionally, in another embodiment, when the reference time
point is determined according to the detected first sequence in
step 202, the reference time point may be determined according to
an index of a symbol that is in the second cell and closest to a
position of the first sequence, where the second cell and the first
cell are deployed on different spectrum resources.
[0171] For example, as shown in the embodiments in FIG. 3a and FIG.
3b, the second cell serving as the reference time source and the
first cell are deployed on different spectrum resources. For
example, the first cell may work on an unlicensed spectrum, and the
second cell may work on a licensed spectrum.
[0172] This embodiment is similar to the foregoing embodiment of
determining a reference time point according to time
synchronization information of the first cell. A difference is that
"according to the time synchronization information of the first
cell" in the foregoing embodiment is replaced with "according to
the time synchronization information of the second cell".
[0173] For example, the index of the symbol that is in the second
cell and closest to the position of the detected first sequence may
be determined as the reference time point. Herein the second cell
may also be replaced with another reference time source. In this
embodiment of the present invention, the reference time source is
not limited only to a cell using a licensed spectrum to perform
data transmission, and may also be in another form, for example, a
GPS or a wired network clock synchronization protocol, for example,
the IEEE 1588 protocol, or a synchronization source base station in
RIBS. Such a replacement still falls within the scope of this
embodiment of the present invention.
[0174] Herein it should be noted that, if there is an offset
between an understanding by the first cell and an understanding by
the second cell about time synchronization, for example, there is a
fixed time offset between the first cell and the second cell, the
determining a reference time point according to the detected first
sequence further includes: determining the reference time point
according to an index of a symbol that is in the second cell and
closest to a position of the first sequence and the time offset
between the first cell and the second cell. The time offset between
the first cell and the second cell may be indicated by an integer
quantity of OFDM symbols, or may be indicated by an integer
quantity of timeslots, or may be indicated by other time units, for
example, the reciprocal Ts of the sampling rate in the LTE system
mentioned in the foregoing embodiment. The UE may obtain the time
offset between the first cell and the second cell by itself through
detection. For example, the UE may determine the time offset
between the first cell and the second cell by using the obtained
time synchronization information of the first cell and time
synchronization information of the second cell. The time offset
between the first cell and the second cell may also be learned by
the UE in a signaling notification manner. For example, the first
cell and the second cell listen to synchronization signals of each
other because they are co-sited or by using a backhaul link
(backhaul), for example, an X2 or S1 interface, or through a
mobility management entity (Mobility Management Entity, MME), or
through air-interface signaling interaction, or through an air
interface, and may learn the time synchronization information each
other, and therefore learn a time offset between time
synchronization information of the peer and its own time
synchronization information. Therefore, the first cell and/or the
second cell may notify the time offset to the UE.
[0175] On the base station side, the first cell determines the
synchronization information of the first cell according to the
synchronization information of the second cell. The first cell
determines the subframe boundary, symbol boundary, timeslot
boundary, frame boundary, super frame boundary, and the like of the
first cell according to the synchronization information of the
second cell. Time boundary alignment, for example, subframe
alignment, timeslot alignment, symbol alignment, frame alignment,
or super frame alignment may be performed between the first cell
and the second cell, or there may be a fixed time offset between
the time boundary of the first cell and the time boundary of the
second cell. Afterward, the first cell sends, according to a time
point at which the first cell seizes an opportunity to use an
unlicensed spectrum resource, the first signal starting from a
position of an index of a symbol that is after the time point and
closest to the time point or starting from a position of an index
of a symbol that is after the time point and has a specific
distance from the time point, where the first signal carries the
first sequence, and the specific distance may be learned by the
cell and/or the UE in a manner of predefinition, standard
specification, or signaling interaction.
[0176] The UE side may learn, according to the time information of
the second cell and with or without reference to the time offset
understood in time between the first cell and the second cell, the
time position of the signal carrying the first sequence in the
first cell, and determine the position or a variation of the
position as the reference time point. For example, the UE may use
an index of a symbol that is in the second cell and before the
position of the detected first sequence and closest to the detected
position as the reference time point; or the UE may use an index of
a symbol that is in the second cell and after the position of the
detected first sequence and closest to the detected position as the
reference time point; or the UE may determine the time information
of the first cell according to the time information of the second
cell and the time offset understood in time between the first cell
and the second cell, and then use, according to the time
information of the first cell, an index of a symbol that is closest
to the position of the detected first sequence or an index of a
symbol having a specific distance relationship as the reference
time point.
[0177] Optionally, in another embodiment, the position of the
foregoing first sequence includes a start time position of the
first sequence. Assuming that the signal carrying the first
sequence occupies one OFDM symbol in time for performing
transmission, the start time position of the first sequence,
namely, an OFDM symbol position occupied by the signal carrying the
first sequence, may be indicated by a symbol index of the OFDM
symbol. If the signal carrying the first sequence occupies multiple
OFDM symbols in time, for example, the first signal occupies
multiple OFDM symbols, in this embodiment of the present invention,
the start time position of the first sequence may be the start
position of the first signal, or more generally, the position of
the first sequence may further be any one or more positions from
the start time position to the end time position of the first
signal. However, a specific form of the position of the first
sequence is not limited in this embodiment of the present
invention. For example, the position of the first sequence may also
be an end time position of the first sequence. Assuming that a time
length of the first sequence is known or preset, the start time
position of the first sequence and the end time position of the
first sequence may be mutually deduced. In different implementation
manners of determining the reference time point according to the
detected first sequence, not only the reference time point can be
determined, but also a problem of ambiguously determining the start
position of the first sequence by the UE is resolved. Especially
when the UE determines the reference time point of the first cell
by using the time information of the second cell, the following
problem exists: Because a signal sent by the first cell and a
signal sent by the second cell arrive in different time positions
on the UE side, the UE determines the reference time point of the
first cell incorrectly. Specifically, assuming that the first cell
is a cell deployed on the unlicensed spectrum, and that the second
cell is a cell deployed on the licensed spectrum, a synchronization
requirement defined for CA (inter-band CA) between different
frequency bands according to a current LTE protocol specification
is that a synchronization error between cells aggregated in the CA
manner is not greater than 260 nanoseconds. However, considering
problems such as propagation delays from different cells to the UE
side, on the UE side, when signals simultaneously sent by cells
aggregated in the CA manner arrive at the UE side, an allowed
synchronization error is not greater than 30.26 microseconds. 30.26
microseconds is approximately equal to a length of a half OFDM
symbol. Therefore, on the UE side, if the OFDM symbol boundary of
the first cell is determined based on the OFDM symbol boundary of
the second cell, determining confusion may exist. For example, the
start sending position of the first signal in the first cell is a
k.sup.th OFDM symbol, and symbol boundaries of the k.sup.th OFDM
symbol of the first cell and a k.sup.th OFDM symbol of the second
cell are aligned. When signals of the first cell and the second
cell arrive at the UE side, the symbol boundary of the first cell
and the symbol boundary of the second cell that are received by the
UE are not aligned, and there is a difference of 30.26
microseconds. In this case, when the UE determines the start
sending position of the first signal in the first cell according to
the symbol boundary of the second cell, the UE cannot determine
whether the start sending position of the received first signal
sent by the first cell is the k.sup.th OFDM symbol, a (k-1).sup.th
OFDM symbol, or a (k+1).sup.th OFDM symbol. In the manner of the
foregoing embodiment, the UE may clearly learn an OFDM index number
of the first cell, and accurately determine a position of the first
signal, for example, the start time position of the first
signal.
[0178] Optionally, in another embodiment, when the position of the
data channel is determined according to the determined reference
time point in step 203, if a time length between the determined
reference time point and an end boundary of the first subframe is
not less than X1, it may be determined that the position of the
data channel is located in the first subframe. X1 is a time length
that is not less than 0.
[0179] The end boundary of the subframe may be understood as an end
time point of a last symbol of the subframe, or may be understood
as a start time point of a subframe next to the subframe, or may be
understood as a boundary time point between the subframe and a
subframe next to the subframe.
[0180] Herein X1 may be preset. For example, X1 may be predefined,
or configured by a network, or learned by a base station or UE in a
signaling manner, for example, learned by the base station through
a backhaul link (an X2 interface or an S1 interface), or learned by
the UE by using signaling (physical signaling, higher layer
signaling, or MAC signaling). In an embodiment, X1 may indicate a
quantity of OFDM symbols (or a quantity of fractional OFDM symbols)
occupied by control information that can support data transmission
between the first cell and the UE and is required for supporting
the data transmission, in the first subframe. Herein the data
transmission between the first cell and the UE includes control
data transmission and/or service data transmission. The control
data includes, for example, control data carried on at least one of
the following control channels in the LTE system: data carried on a
PDCCH, an EPDCCH, a PCFICH, a PHICH, or a PBCH. The service data
includes, for example, service data carried on at least one of the
following data channels: data carried on a PDSCH or a PMCH. The
control information required for supporting the data transmission
may include at least one of the following: the spectrum identifier
of the unlicensed spectrum, the cell identity of the first cell,
the public land mobile network (Public Lands Mobile Network, PLMN)
identifier of the first cell, the synchronization information of
the first cell, or information indicating that the first cell
performs data transmission by using the unlicensed spectrum (for
example, whether the first cell performs data transmission by using
the unlicensed spectrum may be determined by detecting whether the
information exists), where the synchronization information of the
first cell may be implemented by using a reference signal sent by
the first cell, and may include a PSS, an SSS, a CRS, a DMRS, a
CSI-RS, a PRS, a UE-specific reference signal, or a DRS. The
following uses a quantity of OFDM symbols as an example for
description.
[0181] Assuming that the determined reference time point is a
symbol index corresponding to the start position of the first
signal, X1 may be indicated by Xa+Xb, where Xa may indicate a
minimum value of a quantity of OFDM symbols that may be supported
in a subframe by the LTE system and are used for data transmission,
Xb may indicate a minimum value of a quantity of OFDM symbols that
carry necessary control information to support data transmission in
the subframe of the LTE system, for example, Xb=4. In the four OFDM
symbols, a signal carried by the first OFDM symbol may be used to
determine whether the first cell uses the unlicensed spectrum to
perform data transmission, and may be obtained in a manner of
performing energy detection and/or signal parsing on the signal
carried by the first OFDM symbol; any one or more of signals
carried by the first OFDM symbol to the fourth OFDM symbol may be
used to determine the reference time point; and any one or more of
the signals carried by the first OFDM symbol to the fourth OFDM
symbol may be used to determine the synchronization information of
the first cell, for example, enabling the UE to obtain time
synchronization and/or frequency synchronization of the first cell.
If the time length between the determined reference time point and
the boundary of the first subframe is not less than X1, the
following fact is indicated: Starting from successfully seizing an
opportunity to use the unlicensed spectrum, and before the end of
the first subframe, a quantity of OFDM symbols included in this
range in the first subframe may support normal data transmission
between the first cell and the UE. Herein the normal data
transmission means that the quantity of the OFDM symbols included
in the foregoing range in the first subframe may help the UE to
obtain necessary information for data demodulation (for example,
the foregoing control information required for supporting the data
transmission) and perform data transmission (for example, the
foregoing control data transmission and/or service data
transmission between the first cell and the UE).
[0182] Referring to examples in FIG. 4a and FIG. 4b, a detailed
description is provided. FIG. 4a and FIG. 4b are schematic diagrams
of signal positions according to an embodiment of the present
invention.
[0183] In the embodiments in FIG. 4a and FIG. 4b, assuming Xa=3 and
Xb=4, the reference time point is a symbol index corresponding to
the start position of the first signal. The reference time point is
located in the first subframe, that is, in a subframe of the first
cell that is aligned with a subframe #N of the second cell shown in
FIG. 4a and FIG. 4b. In this case, the start position of the first
signal is from 0 (as shown in FIG. 4a) to 7 (as shown in FIG. 4b),
and all positions of the data channel may be located in the first
subframe.
[0184] In this embodiment of the present invention, the first
signal may occupy only one OFDM symbol in time, for example, an
OFDM symbol filled in black in FIG. 4a and FIG. 4b. The first
signal may also occupy multiple OFDM symbols in time, for example,
the OFDM symbol filled in black in FIG. 4a and FIG. 4b and one,
two, or three OFDM symbols after the OFDM symbol. At least one of
the OFDM symbols occupied by the first signal in time carries the
first sequence.
[0185] It should be noted that, in this embodiment of the present
invention, X1 may further include only Xa and exclude Xb, or Xa and
Xb have an overlapping part of OFDM symbols, that is, OFDM symbols
(a quantity may be indicated by Xb) carrying necessary control
information may overlap OFDM symbols carrying data transmission (a
quantity may be indicated by Xa), where the necessary control
information and the data transmission may be multiplexed in X1 OFDM
symbols by time-division multiplexing, frequency division
multiplexing, code division multiplexing, space division
multiplexing, or the like. More specifically, in this embodiment of
the present invention, the OFDM symbol carrying the first signal
may overlap an OFDM symbol used for control data transmission
and/or service data transmission.
[0186] For example, assuming X1=Xa=3, in this case, the first
signal overlaps the data channel. Whether the first cell uses the
unlicensed spectrum to perform data transmission may be determined
by performing energy detection and/or signal parsing on any one or
more of the three OFDM symbols. All the three OFDM symbols may be
used for PDCCH transmission. On time-frequency resources included
in the three OFDM symbols, some specific REs may be used for
carrying necessary control information, for example, a reference
signal. A rule for mapping the reference signal on a time-frequency
resource is similar to a reference signal mapping rule supported by
the LTE system. Assuming that a start position of the PDCCH is a
time point at which the first cell starts to occupy the unlicensed
spectrum, when the reference signal is mapped, the start position
of the PDCCH may be mapped to a first OFDM symbol in a subframe, or
the start position of the PDCCH may be mapped to a symbol position
in the first subframe. For example, it is assumed that the start
position of the PDCCH is a tenth OFDM symbol of the first subframe
and that the PDCCH occupies three OFDM symbols, that is, the PDCCH
occupies the tenth OFDM symbol, an eleventh OFDM symbol, and a
twelfth OFDM symbol. In this case, a symbol carrying the necessary
control information may overlap the three OFDM symbols. For
example, the reference signal may be carried in REs included in any
one or more of the three OFDM symbols, and a rule for mapping the
reference signal on a time-frequency resource may be mapping
according to that of a first OFDM symbol, a second OFDM symbol, or
a third OFDM symbol in a subframe in the existing LTE system, or
may be mapping according to that of a tenth OFDM symbol, an
eleventh OFDM symbol, or a twelfth OFDM symbol in a subframe in the
existing LTE system. More generally, the rule for mapping the
reference signal in the three OFDM symbols may also be redefined.
The mapping rule may be learned by the UE in a manner of
predefinition, standard specification, or signaling
notification.
[0187] When OFDM symbols (a quantity may be indicated by Xb)
carrying necessary control information may overlap OFDM symbols
carrying data transmission (a quantity may be indicated by Xa),
detecting the first signal may be detecting a signal carried on the
unlicensed spectrum by using a possible control data and/or service
data format, including signal parsing and/or energy detection. For
example, a possible format of a PDCCH carrying information, namely,
a downlink control information (Downlink Control Information, DCI)
format, may be used to detect a signal on the unlicensed spectrum.
Herein if the first cell has seized an opportunity to send data on
the unlicensed spectrum, the signal carried on the unlicensed
spectrum may include: transmitted control data and/or service data.
If the first cell has not seized an opportunity to send data on the
unlicensed spectrum, the signal carried on the unlicensed spectrum
does not include a signal sent by the first cell on the unlicensed
spectrum. The first sequence of the detected first signal may
include a DCI format matching the detected signal carried by the
PDCCH. If the matched DCI format is detected, it may be considered
that the first cell has preempted the unlicensed spectrum, or if an
energy detection result of the DCI format exceeds a particular
threshold, it may be considered that the first cell has preempted
the unlicensed spectrum. In this case, the determining a reference
time point according to a first sequence of the detected first
signal may be determining the reference time point according to any
one or more OFDM symbol positions of the PDCCH in time. Further,
the first signal may be DCI in a specific format, or DCI carried on
a specific time-frequency resource. In addition, the first signal
may be public DCI in the first cell, or may be UE-specific DCI, or
may be DCI specific to a particular group of UEs. Evidently, the UE
can detect the first signal only after learning the format of the
first signal.
[0188] Alternatively, when OFDM symbols (a quantity may be
indicated by Xb) carrying necessary control information may overlap
OFDM symbols carrying data transmission (a quantity may be
indicated by Xa), detecting the first signal may be detecting
whether there is a specific signal on a specific time-frequency
resource, where the specific signal may include one or more of a
PSS, an SSS, a CRS, a DMRS, a CSI-RS, a PRS, a UE-specific
reference signal, or a DRS. The channel carrying data transmission
may be mapped on any time-frequency resource except the
time-frequency resource carrying the specific signal. In this case,
detecting the first signal may be detecting whether there is a
specific signal by performing related energy detection or by using
other detection methods. The first sequence of the detected first
signal may be a sequence included in the detected specific signal,
for example, sequences forming the PSS, the SSS, the CRS, the DMRS,
the CSI-RS, the PRS, the UE-specific reference signal, or the DRS.
The reference time point is determined according to the first
sequence.
[0189] In another embodiment, the first signal may also be a part
of the data channel. For example, the first signal is just a
control data channel.
[0190] In the following embodiment, unless otherwise specified,
examples in which the first signal does not overlap the data
channel are mainly used for description. However, the examples may
also be modified according to the foregoing manner, as an
embodiment in which the first signal overlaps the data channel
partially or completely, or the first signal is a part of the data
channel. Such a modification still falls within the scope of the
embodiment of the present invention.
[0191] When lengths of the first signal and the second signal are
different, for example, the second signal includes the first
signal, the time length of the second signal may be further
determined.
[0192] Optionally, in another embodiment, the receive end may
further determine that the time length of the second signal is M1,
where the second signal includes the first signal, and M1 is a
minimum time length of the second signal.
[0193] Specifically, herein M1 may be predefined, or configured by
the network, for example, learned by the base station through a
backhaul link, or learned by the UE by using signaling (physical
layer signaling, higher layer signaling, or MAC signaling).
[0194] For example, referring to the embodiments in FIG. 4a and
FIG. 4b, M1 may be equal to 4, that is, a preset minimum time
length of the second signal may be a quantity of OFDM symbols
occupied by control information required for supporting data
transmission. In other words, M1 may correspond to the foregoing
parameter Xa. In a case in which the start position of the first
signal is from 0 to 7, the UE may determine that the time length of
the second signal is 4.
[0195] If a quantity of OFDM symbols occupied by the first signal
in time is less than a quantity of OFDM symbols occupied by the
second signal in time, for example, in this embodiment, a quantity
of OFDM symbols occupied by the first signal in time is less than
4, the second signal includes the first signal. In this case, when
the UE detects the first signal, the UE may detect the first signal
according to the format of the first signal, for example, the time
length and/or carried content of the first signal. Then the UE may
determine the reference time point according to the first sequence
of the detected first signal, and further determine the position of
the data channel and the length of the second signal. In this
embodiment, whether the length of the second signal is equal to M1
may be determined according to the determined reference time
point.
[0196] If a quantity of OFDM symbols occupied by the first signal
in time is equal to a quantity of OFDM symbols occupied by the
second signal in time, for example, in this embodiment, a quantity
of OFDM symbols occupied by the first signal in time is equal to 4,
the first signal is the second signal. Likewise, in this case, when
detecting the first signal, the UE may detect the first signal
according to the format of the first signal, for example, the
length of the first signal. This is equivalent to a fact that the
UE has determined the length of the second signal. If the UE has
detected the first sequence of the first signal, the UE may
determine that the first cell has sent the first signal. Because in
this process, the UE has considered the time length of the first
signal when detecting the first signal, once the UE determines that
the first cell has sent the first signal, the UE may determine the
time length of the first signal, which is equal to the time length
of the second signal.
[0197] In this embodiment of the present invention, if symbol
lengths of the first signal and the second signal are different, a
detection process of the UE may be simplified, that is, every
possible length of the first signal does not need to be detected,
and therefore, implementation on the UE side may be simplified.
[0198] In this embodiment of the present invention, if the first
signal is a part of transmission of the data channel, or when a
time unit occupied by the first signal in time overlaps a time unit
occupied by transmission of the data channel in time, the time
length of the second signal may be a transmission time length of a
control data channel and/or a transmission time length of a service
data channel.
[0199] For a purpose of clear description, the following describes
a specific embodiment.
[0200] Assumption: The length of the first signal and the length of
the second signal are not equal; the length of the first signal is
1, the length of the second signal is 4, and X1=7; the reference
time point is the start time position of the first signal, and is
indicated by an OFDM symbol index. In another embodiment, the
reference time point may also be indicated by a time point at which
the first cell successfully seizes an opportunity to use an
unlicensed spectrum resource, or more generally, in this embodiment
of the present invention, the reference time point may be a time
position indicated by any time unit in the first subframe.
[0201] The UE may determine the length of the second signal and the
position of the data channel by performing the foregoing steps. The
information carried by the first signal and the second signal may
be learned by the UE in advance, so that the UE detects the first
signal and the second signal. A manner of the learning may be a
method of predefinition, standard specification, network
configuration, or signaling notification. This is not limited in
this embodiment of the present invention. The UE may obtain,
according to the second signal, some control information used for
data channel demodulation. For example, the control information may
include at least one of the following: the spectrum identifier of
the unlicensed spectrum, the cell identity of the first cell, the
synchronization information of the first cell, information
indicating that the first cell performs data transmission by using
the unlicensed spectrum, or other control information supporting
data transmission between the first cell and the UE. Afterward, the
UE may receive and detect the data channel according to the start
position of the data channel. Specifically, in this example, the
data channel may include a control data channel, used to indicate a
service data transmission format in the current subframe or
indicate a service data transmission format in a non-current
subframe. This is not limited herein. In this case, the UE first
detects the control data channel, for example, the PDCCH, the
EPDCCH, the PCFICH, or the PHICH, and obtains the service data
transmission format indicated by the control channel.
Alternatively, the data channel may not include the control data
channel, but includes only the service data channel. In this case,
the service data transmission format corresponding to the service
data carried by the service data channel may be predefined or
notified in advance on the licensed spectrum. In this way, even if
there is no control data channel, the UE may receive and detect the
service data channel according to the learned service data
transmission format. It should be noted that, when the current LTE
system supports data transmission, impact of different quantities
of OFDM symbols used for data transmission on data rate matching of
the UE is also considered. For example, in a time division duplex
TDD (Time Division Duplexing, TDD) system, for a quantity of OFDM
symbols included in a downlink pilot timeslot (Downlink Pilot Time
Slot, DwPTS), when rate matching is performed, introduction of
different coefficients may be considered, for example, 0.75 and
0.375. When the LTE device performs data transmission by using the
unlicensed spectrum, due to random use of a resource on the
unlicensed spectrum, quantities of OFDM symbols used for data
transmission are more diversified. In this case, considering impact
on data rate matching of the UE, introduction of a new rate
matching table may be considered, or a new rate matching
coefficient is introduced, for example, a real number that is
greater than 0 and less than 0.375, or a real number between 0.375
and 0.75, or a real number between 0.75 and 1, or another numeric
value. This is not limited herein.
[0202] FIG. 5 is a schematic diagram of a signal position according
to another embodiment of the present invention.
[0203] Optionally, in another embodiment, as shown in FIG. 5, when
the position of the data channel is determined according to the
determined reference time point in step 203, if the time length
between the determined reference time point and the end boundary of
the subframe is less than X2, it is determined that the position of
the data channel is located in the second subframe, where the
second subframe is a next subframe adjacent to the first subframe.
X2 is a time length that is not less than 0.
[0204] Specifically, in the embodiment in FIG. 5, the first
subframe is a subframe of the first cell that is aligned with the
subframe #N of the second cell, and it is assumed that X2 is equal
to 7.
[0205] If the time length between the determined reference time
point and the boundary of the first subframe is less than X2, it
indicates that, starting from successfully seizing an opportunity
to use the unlicensed spectrum, and before the end of the first
subframe, a quantity of OFDM symbols included in this range in the
first subframe is not enough to support normal data transmission
between the first cell and the UE. Herein the normal data
transmission refers to a minimum quantity of OFDM symbols that may
help the UE to obtain necessary information for data demodulation
and perform data transmission. In addition, the normal data
transmission may also be a minimum quantity of OFDM symbols for
performing data transmission between the first cell and the UE.
Herein the data transmission includes transmission of control data
and service data, for example, data carried in one or more channels
in the PDCCH, the PCFICH, the PHICH, the EPDCCH, the PDSCH, or the
PMCH. In this case, to ensure normal data transmission on the
unlicensed spectrum, the data channel may be located in a next
subframe adjacent to the first subframe in the first cell.
[0206] As shown in FIG. 5, assuming that the reference time point
is a symbol index corresponding to the start position of the first
signal, when the start position of the first signal is any index
from 8 to 10, the position of the data channel is located in a
subframe next to the first subframe, that is, the second subframe
is a subframe of the first cell that is aligned with a subframe
#N+1 of the second cell. Herein the data channel may include a
service data channel and a control data channel, or may include
only a service data channel, or include only a control data
channel. When the data channel includes only a service data
channel, a transmission format of the service data channel is
predefined or is notified in advance by using the licensed
spectrum, that is, content carried on the control data channel
supporting demodulation of the service data transmission channel is
learned by the UE in a manner of predefinition or advance
notification, so that the UE can demodulate the service data
channel.
[0207] FIG. 6 is a schematic diagram of a signal position according
to another embodiment of the present invention.
[0208] Optionally, in another embodiment, as shown in FIG. 6, when
the position of the data channel is determined according to the
determined reference time point in step 203, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than X2, it is determined that the
position of the data channel is located in a third subframe, where
the third subframe is a next subframe that is in the second cell
and adjacent to the first subframe in time. Herein the second cell
and the first cell are deployed on different spectrum resources. X2
is a time length that is not less than 0.
[0209] Specifically, in the embodiment in FIG. 6, the first
subframe is a subframe of the first cell that is aligned with the
subframe #N of the second cell, and it is assumed that X2 is equal
to 7.
[0210] If the time length between the determined reference time
point and the boundary of the first subframe is less than X2, it
indicates that, starting from successfully seizing an opportunity
to use the unlicensed spectrum, and before the end of the first
subframe, a quantity of OFDM symbols included in this range in the
first subframe is not enough to support normal data transmission
between the first cell and the UE. Herein the normal data
transmission refers to a minimum quantity of OFDM symbols that may
help the UE to obtain necessary information for data demodulation
and perform data transmission. Herein the data channel may include
a service data channel and a control data channel. In addition, the
normal data transmission may also be a minimum quantity of OFDM
symbols for performing data transmission between the first cell and
the UE. Herein the data transmission includes transmission of
control data and service data, for example, data carried in one or
more channels in the PDCCH, the PCFICH, the PHICH, the EPDCCH, the
PDSCH, or the PMCH. In this case, to ensure normal data
transmission on the unlicensed spectrum, only the service data
channel may be carried in a next subframe that is in the first cell
and adjacent to the first subframe, but the control data channel
may be carried in a next subframe that is in the second cell and
adjacent to the first subframe, for example, in a cross-carrier
scheduling manner, so that the control data channel carried in the
second cell indicates a transmission format of the service data
channel carried in the first cell, and that the UE can demodulate
the service data channel.
[0211] As shown in FIG. 6, assuming that the reference time point
is a symbol index corresponding to the start position of the first
signal, when the start position of the first signal is any index
from 8 to 10, the position of the service data channel is located
in a subframe next to the first subframe, that is, the second
subframe is a subframe of the first cell that is aligned with the
subframe #N+1 of the second cell, and the third subframe is the
subframe #N+1 of the second cell.
[0212] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is not less than Y1, the receive end may further
determine that the time length of the second signal is Z1, where
the second signal includes the first signal, Z1 belongs to a length
set {L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of
the second signal is located at the end boundary of the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a
time length that is not less than 0. More specifically, Y1 may be a
time length that is not equal to X2 and not less than 0.
[0213] In this embodiment, when the time length between the
reference time point and the end boundary of the first subframe is
greater than the length of the second signal having a minimum time
length, remaining symbols of the first subframe may be used for
repeating content of the second signal or used for sending a
reservation signal (for example, a padding or a preamble).
[0214] Assuming that the determined reference time point is the
start time position of the first signal, or is a start time point
at which a spectrum resource is successfully preempted on the
unlicensed spectrum, Y1 may indicate the preset minimum time length
of the second signal. Assuming that Y1 is equal to 4, when a
quantity of OFDM symbols between the start position of the first
signal and the boundary of the subframe is less than 7 and greater
than or equal to 4, because a transmission position of the data
channel is located in a next subframe (namely, the foregoing second
subframe) that is in the first cell and adjacent to the first
subframe and/or a next subframe (namely, the foregoing third
subframe) that is in the second cell and adjacent to the first
subframe, to prevent another device working on the unlicensed
spectrum from preempting the unlicensed spectrum resource, the end
time position of the second signal may be located at the end
boundary of the first subframe. For example, referring to FIG. 6,
the determined length of the second signal may be six OFDM symbols,
five OFDM symbols, or four OFDM symbols, where 4, 5, and 6 may
correspond to elements in the foregoing length set {L.sub.1,
L.sub.2, . . . L.sub.n}. A signal that is greater than four OFDM
symbols may be formed by repetitions of a second signal having a
length of four OFDM symbols, or a reservation signal (padding) may
be sent after a second signal having a length of four OFDM symbols
until the end boundary of the first subframe is reached.
[0215] In an embodiment similar to FIG. 4a and FIG. 4b, for various
cases in which a quantity of OFDM symbols occupied by the first
signal in time is the same as a quantity of OFDM symbols occupied
by the second signal in time, the UE has a corresponding detection
process. A slight difference is that, when the length of the first
signal is the same as the length of the second signal, because
herein the length of the second signal varies according to the
reference time point, the UE may detect the first signal by using
all possible lengths of the second signal (namely, possible lengths
of the first signal), and once the first sequence of the first
signal is detected, may determine the length of the second
signal.
[0216] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y2, it is determined that the time
length of the second signal is Z2, where the second signal includes
the first signal, Z2 belongs to a length set {L.sub.1', L.sub.2', .
. . L.sub.n'}, and the end time position of the second signal is
located in the second subframe of the first cell. The second
subframe is a next subframe adjacent to the first subframe, n is an
integer not less than 1, .A-inverted.i, 1.ltoreq.i<n,
L.sub.i'<L.sub.i+1', and Y2 is a time length not less than 0.
Further, Y2 may be a time length that is not equal to X2 and not
less than 0.
[0217] In this embodiment, when the time length between the
reference time point and the end boundary of the first subframe is
less than a normal length of the second signal, a part of the
second signal may be extended to a next subframe for continuing
sending. The normal length of the second signal generally refers to
a minimum time length that meets a control information transmission
requirement.
[0218] Specifically, assuming that Y2 may indicate the minimum time
length of the second signal, if the time length between the
determined reference time point and the end boundary of the first
subframe is less than Y2, if considered from a perspective of
ensuring performance, a symbol length of the second signal may be
greater than or equal to Y2, that is, the length of the second
signal may belong to the length set {L.sub.1', L.sub.2', . . .
L.sub.n'}, for example, may be 4, 5, or 6. In this case, the second
signal needs to be extended to a next subframe (namely, the
foregoing second subframe) that is in the first cell and adjacent
to the first subframe. Starting from the end position of the second
signal, transmission of the data channel may be performed in the
first cell. In addition, in a case of cross-carrier scheduling, the
control data channel may start to be transmitted from a start
boundary of a next subframe (namely, the foregoing third subframe)
that is in the second cell and adjacent to the first subframe, or
may start to be transmitted from a particular position included in
the third subframe.
[0219] In another embodiment, if some OFDM symbols of the second
signal overlap some OFDM symbols of the data channel carried by the
second subframe, the data channel carried by the second subframe
may also start to be transmitted from the start boundary of the
second subframe. In this case, information carried by OFDM symbols
that are reused for the second signal and the data channel carried
by the second subframe may be multiplexed on the resources with the
data channel. For example, assuming that the second signal occupies
four OFDM symbols in time, where the last two symbols carry a
reference signal that may provide synchronization information, such
as a CRS, a CSI-RS, a PRS, or DMRS, and also assuming that the data
channel that starts to be transmitted from the second subframe is a
control data channel such as a PDCCH, information carried by the
last two symbols of the second signal may be multiplexed on the
resources with the PDCCH, that is, in this case, the PDCCH may
start to be transmitted from the start boundary of the second
subframe.
[0220] FIG. 7 provides a schematic diagram of occupancy of the
second subframe by the second signal part. Specifically, FIG. 7 is
a schematic diagram of a signal position according to another
embodiment of the present invention. As shown in FIG. 7, the first
subframe is a subframe of the first cell that is aligned with the
subframe #N of the second cell, the second subframe is a subframe
of the first cell that is aligned with the subframe #N+1 of the
second cell, and the third subframe is the subframe #N+1 of the
second cell. In FIG. 8, the length of the second signal is four
OFDM symbols, that is, four symbols starting from a symbol filled
in black in FIG. 7. Data transmission in the second subframe by the
first cell starts from the end position of the second signal. If
cross-carrier scheduling is used, control data may also start to be
transmitted from a start position of the third subframe.
[0221] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y3, it is determined that the time
length of the second signal is Z3, where the second signal includes
the first signal. Z3 is less than M2, and the end time position of
the second signal is located at the end boundary of the first
subframe. M2 is the minimum time length of the second signal, and
Y3 is a time length that is not less than 0. More specifically, Y3
may be a preset time length that is not equal to X2 and not less
than 0.
[0222] In this embodiment, when the time length between the
reference time point and the end boundary of the first subframe is
less than the normal length of the second signal, the length of the
second signal may be truncated appropriately.
[0223] Assuming that M2 is equal to 4, if the determined reference
time point is the start time position of the first signal, or is a
start time point at which a spectrum resource is successfully
preempted on the unlicensed spectrum, Y3 may indicate the minimum
time length of the second signal, that is, is equal to the
foregoing parameter M2. In this case, because a quantity of OFDM
symbols included, starting from successfully preempting the
spectrum resource on the unlicensed spectrum to the end boundary of
the first subframe, is not enough to support sending of the second
signal, an optional method is to reduce the minimum length of the
second signal. Generally, meeting a function provided by the second
signal needs to be considered in a design of the minimum length of
the second signal. For example, if the function of the second
signal is to obtain basic synchronization information of the first
cell by using the second signal before the first cell and the UE
perform data transmission by using the unlicensed spectrum, the
minimum length of the second signal is 4. A manner of truncating
the second signal may affect data transmission on the unlicensed
spectrum between the first cell and the UE to some extent, for
example, may reduce precision of tracing synchronization
information of the first cell by the UE. However, if the UE saved
the synchronization information of the first cell previously, for
example, the UE and the first cell previously performed
communication by using the unlicensed spectrum, and the UE saved
historical synchronization information of the first cell, the
truncating solution may be considered in this case, that is, the
length of the second signal is reduced.
[0224] FIG. 8 provides a schematic diagram of a case in which the
second signal is truncated. Specifically, FIG. 8 is a schematic
diagram of a signal position according to another embodiment of the
present invention. As shown in FIG. 8, the first subframe is a
subframe of the first cell that is aligned with the subframe #N of
the second cell, the second subframe is a subframe of the first
cell that is aligned with the subframe #N+1 of the second cell, and
the third subframe is the subframe #N+1 of the second cell. The
receive end determines, according to the length between the
reference time point and the end boundary of the first subframe,
that the length of the second signal is truncated to two or three
OFDM symbols.
[0225] Optionally, in another embodiment, when the position of the
data channel is determined according to the determined reference
time point in step 203, if the time length between the determined
reference time point and the end boundary of the first subframe is
less than X3, and the time length between the determined reference
time point and the end boundary of the first subframe is greater
than Y4, the receive end may determine that the position of the
data channel is located in the first subframe, where X3 and Y4 are
time lengths that are not less than 0, and Y4 is not greater than
X3.
[0226] In this embodiment, when the time length between the
reference time point and the end boundary of the first subframe is
greater than the length of the second signal, remaining symbols of
the first subframe may be used for transmitting the data
channel.
[0227] FIG. 9 is a schematic diagram of a signal position according
to another embodiment of the present invention. As shown in FIG. 9,
assuming that X3 is equal to 7 and that Y4 is equal to 4, the
determined reference time point is the start position of the first
signal, the first subframe is a subframe of the first cell that is
aligned with the subframe #N of the second cell, and the second
subframe is a subframe of the first cell that is aligned with the
subframe #N+1 of the second cell. In addition, the reference time
point may also be a start position in which data transmission is
performed when an opportunity to use a spectrum resource on the
unlicensed spectrum is seized. The position of the data channel
such as the service data channel may also be located in the first
subframe. The control information used for demodulating the
information carried by the service data channel may be predefined
or indicated in advance by using the licensed spectrum.
[0228] FIG. 10 is a schematic diagram of a signal position
according to another embodiment of the present invention. Each
parameter in the embodiment in FIG. 10 is the same as that in FIG.
9, and therefore is not described again.
[0229] In the embodiment in FIG. 10, if the time length between the
determined reference time point and the end boundary of the first
subframe is five or six OFDM symbols, the position of the data
channel (for example, a control data channel PDCCH) may be located
in the first subframe, and at the same time, the control data
channel may carry data scheduling information of the second
subframe. Therefore, cross-subframe scheduling or multi-subframe
scheduling is implemented.
[0230] In FIG. 10, the first subframe is a subframe of the first
cell that is aligned with the subframe #N of the second cell, and
the second subframe is a subframe of the first cell that is aligned
with the subframe #N+1 of the second cell.
[0231] For the embodiments in FIG. 9 and FIG. 10, a manner of
determining the length of the second channel may be similar to that
in each of the foregoing embodiments, and therefore is not
described again.
[0232] In the foregoing embodiments in FIG. 4 to FIG. 10, a
relationship between the determined reference time point and the
position of the data channel may be stored at the transmit end and
the receive end in a form of a table or the like. This can improve
computation efficiency.
[0233] Optionally, in another embodiment, a correspondence exists
between the reference time point and the position of the data
channel, each reference time point corresponds to one index, and
each index corresponds to one position of the data channel. A
typical manner of expressing the correspondence is a table. The
following describes examples of configuration tables of
correspondences that may be used in this embodiment of the present
invention with reference to specific examples. However, it should
be noted that, the examples are only illustrative. A person skilled
in the art can easily obtain equivalent tables of the tables or
equivalent expression manners, and all the equivalent manners fall
within the scope of this embodiment of the present invention.
[0234] Assuming that the reference time point is the start sending
position of the first signal, or is a start time point at which an
opportunity to use the unlicensed spectrum is successfully seized,
and that the reference time point is indicated by an OFDM symbol
index in a subframe, a form of the foregoing correspondence table
is shown in Table 2.
TABLE-US-00002 TABLE 2 Configuration example of a correspondence
between reference time point and data channel Position of a
reference time point (OFDM symbol Configuration index in index a
subframe) Position of a data channel 0 0 In the same subframe as
the reference time point 1 1 In the same subframe as the reference
time point 2 2 In the same subframe as the reference time point 3 3
In the same subframe as the reference time point 4 4 In the same
subframe as the reference time point 5 5 In the same subframe as
the reference time point 6 6 In the same subframe as the reference
time point 7 7 In the same subframe as the reference time point 8 8
Not in the same subframe as the reference time point 9 9 Not in the
same subframe as the reference time point 10 10 Not in the same
subframe as the reference time point 11 11 Not in the same subframe
as the reference time point 12 12 Not in the same subframe as the
reference time point 13 13 Not in the same subframe as the
reference time point
[0235] Table 2 may be further simplified, as shown in the following
Table 3.
TABLE-US-00003 TABLE 3 Another configuration example of a
correspondence between reference time point and data channel
Reference time point Configuration (OFDM symbol index index in a
subframe) Position of a data channel 0 Any value from 0 to 7 In the
same subframe as the reference time point 1 Any value from 8 to 13
Not in the same subframe as the reference time point
[0236] Table 3 may be further extended to a more general form, as
shown in Table 4.
TABLE-US-00004 TABLE 4 Another configuration example of a
correspondence between reference time point and data channel
Reference time point Configuration (OFDM symbol index index in a
subframe) Position of a data channel 0 Any value from 0 to K In the
same subframe as the reference time point 1 Any value from K + 1
Not in the same subframe to 13 as the reference time point
[0237] K is an integer that is not less than 0 and not greater than
12.
[0238] Further, time units in the first subframe may be further
grouped into G sets. A universal set of elements included in the G
sets is all time units included in the first subframe. For example,
if a time unit is indicated by an OFDM symbol, all the time units
in the first subframe are symbol indexes of 14 OFDM symbols or
positions of the 14 OFDM symbols in the first subframe. The
elements included in the G sets may have an intersection set, or
may have no intersection set. This is not limited. A case
corresponding to time units included in a part of sets in the G
sets is: the data channel and the reference time point are in the
same subframe. A case corresponding to time units included in
another part of sets in the G sets is: the data channel and the
reference time point are in different subframes.
[0239] In the tables, an example in which the position of the data
channel is not in the same subframe as the reference time point may
include: the reference time point and the position of the data
channel are both located in a same cell, but located in different
subframes; or the reference time point and the position of the data
channel are located in different cells, but located in subframes
having a same subframe index number; or the reference time point
and the position of the data channel are located in different
cells, and located in subframes having different subframe index
numbers.
[0240] In this embodiment of the present invention, content in the
tables may further include other information. For example, the
control data channel included in the data channel is used for at
least one of the following: scheduling a service data channel that
is located in the same subframe as the control data channel,
scheduling a service data channel that is not located in the same
subframe as the control data channel (cross-subframe scheduling or
multi-subframe scheduling), or scheduling a service data channel
that is not located in the same cell as the control data channel
(cross-cell scheduling or cross-carrier scheduling). Content in the
tables may further include other information, for example, the
length of the first signal, and the length of the second
signal.
[0241] In this embodiment of the present invention, further,
content in the tables reflecting the correspondence between the
reference time point and the data channel may be further
dynamically changed or semi-statically changed, or may be
predefined. The network or cell may determine content in the tables
according to service load, an interference level of the unlicensed
spectrum, and the like, and notify the UE on a timely basis. For
example, multiple tables are configured in advance for the network
or cell side, and when the tables are used, which table is
effective may be learned by the UE in a signaling-triggered
manner.
[0242] It should be additionally noted that, in this embodiment of
the present invention, because the LTE device sends the first
signal only after seizing an opportunity to use a spectrum, the
start position of the first signal is related to a time point at
which the LTE device seizes the opportunity to use the spectrum,
and may be further related to a time granularity of a CCA performed
by the LTE device. For example, if a time of a CCA performed by the
LTE device is an OFDM symbol, preferentially, to simplify a system
design and enable the LTE device to start to perform a CCA at a
boundary of each OFDM symbol, once the LTE device seizes an
opportunity to use a spectrum resource on the unlicensed spectrum,
a start time point of data transmission on the unlicensed spectrum
may start from the boundary of the OFDM symbol. Correspondingly,
the UE may also detect the first signal by detecting symbols one by
one on the boundary of the OFDM symbol. For another example, if a
time of a CCA performed by the LTE device is a fractional OFDM such
as a 1/4 OFDM, to simplify a system design, the LTE device may also
divide an OFDM symbol into four equal parts by using an OFDM symbol
boundary, where each equal part corresponds to a time of a CCA. In
this case, once the LTE device seizes an opportunity to use the
unlicensed spectrum, the LTE device may start to perform data
transmission on a time position of a fractional OFDM. An advantage
of using a length of a fractional OFDM lies in that, implementation
complexity of the UE may be reduced, because the UE may receive, by
sampling, a signal carried in a position of a fractional OFDM
symbol, namely, a fractional OFDM symbol, sent on the unlicensed
spectrum, or further detect a signal carried in a position of a
fractional OFDM symbol, namely, a fractional OFDM symbol, sent on
the unlicensed spectrum. If the UE side learns the OFDM symbol
boundary of the unlicensed spectrum, the UE side may learn a
possible start time point of data on the unlicensed spectrum. For
another example, a time of a CCA performed by the LTE device may
also be any time less than a length of one OFDM symbol, and the
foregoing process is also effective. In summary, if a length of a
CCA performed by the LTE device and a boundary of the CCA performed
when the LTE device preempts the unlicensed spectrum may be learned
by another LTE device (or in a broader sense, another device
working on the unlicensed spectrum) that detects whether there is
data transmission on the unlicensed spectrum, this helps the
another LTE device that detects whether there is data transmission
on the unlicensed spectrum to determine a possible start position
for detecting the first signal, or a possible start time point of
data transmission on the unlicensed spectrum. For example, herein
the LTE device may be an entity that controls the first cell in
this embodiment of the present invention, and the another LTE
device is UE in this embodiment of the present invention. To reduce
detection complexity on the LTE device, the LTE device may learn,
in advance, information used for reducing blind detection,
including at least one of the following: the length of the CCA
performed when the LTE device preempts the unlicensed spectrum, the
boundary (for example, an OFDM symbol boundary, or a fractional
OFDM symbol boundary in an OFDM symbol) of the CCA performed by the
LTE device, or the like, a data transmission unit after the LTE
device preempts the unlicensed spectrum, a possible start position
of data transmission, a possible start position of the first
signal, a position of the second signal, or a possible start
position of the second signal. The information may be learned by
the UE in a manner of predefinition, standard specification,
network configuration, or signaling notification. In the signaling
notification manner, the signaling may be carried on the unlicensed
spectrum, or may be carried on the licensed spectrum. To reduce a
quantity of blind detection by the UE and power consumption of the
UE, OFDM symbol alignment (or symbol boundary alignment), timeslot
alignment (or timeslot boundary alignment), subframe alignment
(subframe boundary alignment), radio frame alignment (or radio
frame boundary alignment), or super frame alignment (or super frame
boundary alignment) may be performed on the unlicensed spectrum and
the licensed spectrum. Time unit indexes of the unlicensed spectrum
and the licensed spectrum may be different or may be the same. For
example, a first OFDM symbol on the unlicensed spectrum corresponds
to a second OFDM symbol on the licensed spectrum.
[0243] The foregoing embodiments in FIG. 3 to FIG. 10 may be
independent of each other, or may be mutually combined or mutually
referenced. For example, parameters of a same type described in
different embodiments such as X, Y, Z, or M may use a same value or
structure, or may use different values or structures. An embodiment
obtained after the combination also falls within the scope of the
embodiments of the present invention.
[0244] FIG. 11 is a schematic flowchart of a data transmission
method according to another embodiment of the present invention.
The method in FIG. 11 is performed by a transmit end (for example,
an LTE device, such as an LTE base station or UE).
[0245] 1101. Determine a reference time point, where the reference
time point is located in a first subframe of a first cell.
[0246] 1102. Determine a sending position of a first signal
according to the reference time point, and send the first signal in
the sending position of the first signal.
[0247] 1103. Determine a position of a data channel according to
the reference time point, and send the data channel in the
determined position of the data channel.
[0248] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
system overheads are reduced and spectral usage efficiency is
improved.
[0249] It should be noted that, similar attributes such as "first",
"second", and "third" before terms in the specification of the
present invention are not used to limit a sequence of the terms,
but used only for distinguishing. For example, "first signal" and
"second signal" mean that the two signals may represent different
signal carriers. In other words, the two signals may also represent
a same signal carrier, but anyway, the two signals do not mean that
the first signal is located before the second signal in time. If a
sequence relationship exists definitely, it is particularly pointed
out in the specification of the present invention.
[0250] The first cell may be a cell on an unlicensed spectrum. The
first signal may be used to indicate that a transmit end has
preempted a spectrum resource of the first cell on the unlicensed
spectrum. A preemption operation in this embodiment of the present
invention may include a preemption operation performed according to
a backoff process in FIG. 1, or may include preemption operations
in other forms, for example, an unlicensed spectrum resource
pattern (pattern) preset according to a protocol specification. For
example, the first signal may indicate, to a receive end in an
explicit or implicit manner, that the transmit end has preempted a
spectrum resource on the unlicensed spectrum. In an embodiment, the
explicit manner may be that the first signal may carry a specific
flag (flag) field or a similar indication field, and different flag
values indicate whether an unlicensed spectrum resource is
preempted. In another embodiment, the implicit manner may be that
sending the first signal or not is used to indicate whether the
transmit end has preempted an unlicensed spectrum resource. For
example, an action of sending the first signal indicates that the
transmit end has preempted an unlicensed spectrum resource. In
addition, the first signal may be used for other purposes, for
example, used for synchronizing or transmitting other useful
information.
[0251] The first cell in this embodiment of the present invention
may be a cell deployed on the unlicensed spectrum. One of functions
of the first signal is that the receive end determines, by
detecting the first signal, whether the first cell that sends the
first signal has data transmission on the spectrum on which the
first cell is deployed. For example, when the first cell is
deployed on the unlicensed spectrum, the receive end may determine,
by detecting the first signal, whether the first cell starts to use
the unlicensed spectrum or whether the first cell seizes an
opportunity to use a spectrum resource on the unlicensed spectrum.
The first signal may be a reference signal, for example, may be one
of the following reference signals: a PSS, an SSS, a CRS, a CSI-RS,
a PRS, a DRS, a DMRS, or a UE specific reference signal used for
PDSCH demodulation. In another embodiment, the first signal in this
embodiment of the present invention may also be a channel carrying
data, for example, one of the following channels: a PDCCH, a PDSCH,
an EPDCCH, or the like.
[0252] The first signal includes or carries a first sequence. For
example, the first sequence has N different sequence forms, and no
matter which sequence form is used for the first sequence, the
first sequence may be included in the first signal. UE may
determine, by detecting the first signal, the first sequence (for
example, the sequence form of the first sequence) included in the
first signal, and this may be referred to as the first sequence of
the detected first signal. More specifically, for example, a PSS in
an existing LTE system is used as the first signal; in this case,
the first sequence may be Zadoff-Chu sequences forming the PSS; and
the UE may determine, by detecting the PSS, which Zadoff-Chu
sequence, namely, which first sequence, is carried in the detected
PSS. For another example, an SSS in the existing LTE system is used
as the first signal; in this case, the first sequence may be 168
sequences forming the SSS, and any one in the 168 sequences is a
combination of two binary sequences having a length of 31. In
addition, the first signal may also be a channel including or
carrying the first sequence. In this embodiment of the present
invention, the term signal or channel may indicate a carrier that
is used to carry specific information or data and occupies a
specific time-frequency resource.
[0253] The data channel may be independent of the first signal, for
example, may be sent after the first signal. The data channel and
the first signal may also occupy a same time resource, for example,
are multiplexed on the time resource in orthogonal mode such as
frequency division, space division, or code division. The data
channel may be used to carry control data and/or service data. An
example of the control data includes but is not limited to data
carried by a PDCCH, an EPDCCH, a PBCH, a PHICH, or a PCFICH. An
example of the service data includes but is not limited to data
carried by a PDSCH or a PMCH.
[0254] In addition, in this embodiment of the present invention, a
detection operation of the receive end on the first signal may be
real-time blind detection, for example, detecting whether the first
signal exists during signal reception, or may be first buffering
the first signal and then detecting the first signal.
[0255] In the following embodiment, for ease of description, a case
in which the transmit end is an LTE base station and the receive
end is LTE UE is mainly used as an example for description, that
is, a case in which the first signal and the data channel are a
downlink signal and channel is used as an example for description.
A person skilled in the art easily understands that a case in which
the first signal and the data channel are an uplink signal and
channel may be designed or modified similarly. Such a design or
modification still falls within the scope of this embodiment of the
present invention.
[0256] To implement data communication between the first cell and
the UE on the unlicensed spectrum, once the first cell seizes an
opportunity to use the unlicensed spectrum, before the first cell
performs control data and/or service data transmission with the UE,
the first cell may first send other control information used for
detecting control data and/or service data, or before the first
cell performs control data and/or service data communication with
the UE, the UE needs to first learn other control information used
for detecting control data and/or service data. For example, the
other control information may include information that enables the
UE to determine that the first cell seizes an opportunity to use
the unlicensed spectrum, a cell identity of the first cell,
synchronization information of the first cell, a public land mobile
network (Public Lands Mobile Network, PLMN) identifier of the first
cell, or more generally, necessary control information supporting
data transmission in the current LTE system, for example,
information carried in a PBCH or information carried in a system
information block (System Information Block, SIB). The other
control information may be carried in a signal and/or a channel.
For example, the synchronization information of the first cell may
be carried by a synchronization signal sent by the first cell. In
this embodiment of the present invention, a carrier carrying the
other control information is referred to as a second signal, or may
be referred to as a second channel. For example, the second signal
may be in a form of a preamble (preamble), and the preamble carries
the other control information. However, the form or a specific name
of the second signal is not limited in this embodiment of the
present invention. In this embodiment of the present invention, the
term "signal" is mainly used for description. However, this may
also be extended to a case in which the term "channel" is used, and
the extension falls within the scope of this embodiment of the
present invention. The second signal sent by the first cell may
occupy multiple time units in time. Herein the time unit may be a
length of one OFDM symbol, or may occupy a length of a fractional
OFDM symbol, or may be another length representation form related
to a length of an OFDM symbol, for example, a reciprocal Ts of a
sampling rate, where 15360*Ts=0.5 milliseconds. To implement normal
data communication between the first cell and the UE on the
unlicensed spectrum, from a perspective of a synchronization
requirement meeting normal data communication, the second signal
may occupy X OFDM symbols in time, where X may be any positive
integer. For example, assuming that X is set to 4 to implement a
requirement of frequency synchronization between the first cell and
the UE on the unlicensed spectrum, a signal carried by a first OFDM
symbol may enable the UE to learn whether the first cell has seized
an opportunity to use a spectrum resource on the unlicensed
spectrum. In this case, the UE may learn, by detecting energy of
the first OFDM symbol or parsing (demodulating) the signal carried
by the first OFDM, whether the first cell has seized an opportunity
to use a spectrum resource on the unlicensed spectrum. Certainly,
the time length occupied by the second signal in time may be
determined according to a met function provided by the second
signal.
[0257] The first signal may be a part of the second signal, or may
be just the second signal. For example, the first signal may
include only the first OFDM symbol of the second signal in time.
The UE may determine, by detecting the first signal, whether the
first cell has seized an opportunity to use a spectrum resource on
the unlicensed spectrum.
[0258] Correspondingly, the reference time point and a length of
the second signal are then determined according to the first
sequence of the detected first signal. For another example, the
first signal is just the second signal. The first sequence of the
detected first signal may include a detected signal carrying the
first sequence, where the signal carrying the first sequence is a
part of the first signal.
[0259] The data transmission method performed by the transmit end
is hereinafter described in more detail with reference to specific
embodiments. It should be noted that, for brevity, in the following
embodiments, a process same as or corresponding to that in the
foregoing embodiments in FIG. 2 to FIG. 10 is not described
again.
[0260] Optionally, in an embodiment, when determining the reference
time point in step 1101, the transmit end may determine the
reference time point according to an index of a symbol closest to a
time point at which a spectrum resource of the first cell is
preempted, as described in the embodiments in FIG. 3a and FIG. 3b.
Herein the symbol index may also be replaced with other forms such
as a fractional symbol index or an integer multiple of a reciprocal
of a sampling rate. Embodiments with such replacements all fall
within the scope of this embodiment of the present invention. In
addition, in a time period between the foregoing time point and the
reference time point, the transmit end may send a reservation
signal (padding).
[0261] Optionally, in an embodiment, when determining the reference
time point in step 1101, the transmit end may determine the
reference time point according to an index of a symbol that is in a
second cell and closest to a time point at which a spectrum
resource of the first cell is preempted. Herein the second cell and
the first cell are deployed on different spectrum resources. For
example, the first cell may be the unlicensed spectrum, and the
second cell may be a licensed spectrum or other reference time
sources. Herein the symbol index may also be replaced with other
forms such as a fractional symbol index or an integer multiple of a
reciprocal of a sampling rate. Embodiments with such replacements
all fall within the scope of this embodiment of the present
invention. In addition, in a time period between the foregoing time
point and the reference time point, the transmit end may send a
reservation signal (padding).
[0262] Optionally, in another embodiment, the first signal may
include or carry the first sequence. In this case, the transmit end
may further determine the first sequence according to the reference
time point. For example, the transmit end may determine the first
sequence according to a one-to-one correspondence between sequence
information of the first sequence and the reference time point. In
other words, a one-to-one correspondence may exist between the
sequence information of the first sequence and the reference time
point (for example, in a form of a table). This helps to determine
the corresponding sequence information of the first sequence
according to the reference time point.
[0263] Optionally, in another embodiment, for example, as shown in
FIG. 4a and FIG. 4b, when the position of the data channel is
determined according to the reference time point in step 1103, if a
time length between the reference time point and an end boundary of
the first subframe is not less than X1, it may be determined that
the position of the data channel is located in the first subframe,
where X1 is a time length that is not less than 0.
[0264] Optionally, in another embodiment, for example, as shown in
FIG. 4a and FIG. 4b, the transmit end may further determine that a
time length of a second signal is M1, where the second signal
includes the first signal, and M1 is a minimum time length of the
second signal.
[0265] Optionally, in another embodiment, as shown in FIG. 5, when
the position of the data channel is determined according to the
reference time point in step 1103, if a time length between the
reference time point and an end boundary of the first subframe is
less than X2, it is determined that the position of the data
channel is located in a second subframe, where the second subframe
is a next subframe adjacent to the first subframe.
[0266] Optionally, in another embodiment, for example, as shown in
FIG. 6, when the position of the data channel is determined
according to the reference time point in step 1103, if a time
length between the reference time point and an end boundary of the
first subframe is less than X2, it is determined that the position
of the data channel is located in a third subframe, where the third
subframe is a next subframe that is in the second cell and adjacent
to the first subframe in time. The second cell and the first cell
are deployed on different spectrum resources. X2 is a time length
that is not less than 0.
[0267] Optionally, in another embodiment, for example, as shown in
FIG. 6, if the time length between the reference time point and the
end boundary of the first subframe is not less than Y1, it is
determined that a time length of a second signal is Z1, where the
second signal includes the first signal, Z1 belongs to a length set
{L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of the
second signal is located at the end boundary of the first subframe,
where n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0268] Optionally, in another embodiment, for example, as shown in
FIG. 7, if the time length between the reference time point and the
end boundary of the first subframe is less than Y2, it is
determined that a time length of a second signal is Z2, where the
second signal includes the first signal, Z2 belongs to a length set
{L.sub.1', L.sub.2', . . . L.sub.n'}, an end time position of the
second signal is located in the second subframe of the first cell,
and the second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0269] Optionally, in another embodiment, for example, as shown in
FIG. 8, if the time length between the reference time point and the
end boundary of the first subframe is less than Y3, it is
determined that a time length of a second signal is Z3, where the
second signal includes the first signal, Z3 is less than M2, an end
time position of the second signal is located at the end boundary
of the first subframe, M2 is a minimum time length of the second
signal, and Y3 is a time length that is not equal to X2 and not
less than 0.
[0270] Optionally, in another embodiment, for example, as shown in
FIG. 9, when the position of the data channel is determined
according to the reference time point in step 1103, if the time
length between the reference time point and the end boundary of the
first subframe is less than X3, and the time length between the
reference time point and the end boundary of the first subframe is
greater than Y4, it is determined that the position of the data
channel is located in the first subframe, where X3 and Y4 are time
lengths that are not less than 0, and Y4 is not greater than
X3.
[0271] Optionally, in another embodiment, for example, as shown in
FIG. 6, FIG. 7, and FIG. 10, the data channel may carry data
scheduling information of a second subframe of the first cell,
where the second subframe is a next subframe adjacent to the first
subframe.
[0272] Optionally, in another embodiment, a correspondence exists
between the reference time point and the position of the data
channel, where each reference time point corresponds to one index,
and each index corresponds to one position of the data channel, for
example, as described in the foregoing Table 2 to Table 4.
[0273] Optionally, in another embodiment, the position of the data
channel may include at least one of the following positions: a
position of a control data channel or a position of a service data
channel.
[0274] Therefore, in this embodiment of the present invention, the
determining a position of a data channel according to the reference
time point may include at least one of the following manners:
[0275] determining that the position of the data channel and the
reference time point are in a same subframe;
[0276] determining that the position of the data channel and the
reference time point are in different subframes;
[0277] determining that the position of the data channel and the
reference time point are in different cells;
[0278] determining that the position of the control data channel
and the reference time point are in a same subframe, and that the
control data channel is used for scheduling a service data channel
of the first subframe;
[0279] determining that the position of the control data channel
and the reference time point are in a same subframe, and that the
control data channel may be used for cross-subframe scheduling,
that is, the control data channel may be used for scheduling a
service data channel of a non-first subframe, for example, a
service data channel of another subframe after the first subframe,
where the another subframe and the first subframe may be in a same
cell;
[0280] determining that the position of the control data channel
and the reference time point are in a same subframe, and that the
control data channel may be used for first-subframe scheduling and
cross-subframe scheduling simultaneously;
[0281] determining that a part of positions of the control data
channel and the reference time point are in a same subframe, and
that another part of positions of the control data channel and the
reference time point are in different subframes, and that the
control data channel may be used for cross-subframe scheduling,
that is, the control data channel may be used for scheduling a
service data channel of a non-first subframe, for example, a
service data channel of another subframe after the first subframe,
where the another subframe and the first subframe may be in a same
cell; assuming that the control data channel occupies three OFDM
symbols in time, first two OFDM symbols of the control data channel
may be in the first subframe, the last OFDM symbol may be in a next
subframe that is in the first cell and adjacent to the first
subframe, and the control data channel may indicate a service data
transmission format of the next subframe that is in the first cell
and adjacent to the first subframe;
[0282] determining that the position of the control data channel
and the reference time point are in different subframes; or
[0283] determining that the position of the service data channel
and the reference time point are in a same subframe or in different
subframes, where information used for indicating a transmission
format of the service data channel may be carried by the control
data channel, or is learned by the cell and/or the UE in a manner
of predefinition or advance indication by using the licensed
spectrum.
[0284] In this embodiment of the present invention, to support the
UE in detecting a data channel and especially a control data
channel in different cells, dynamic signaling may be used to
instruct the UE to perform cross-carrier detection, so that the UE
can quickly switch from detecting a channel of the first cell to
detecting a channel of the second cell.
[0285] In this embodiment of the present invention, PDCCH formats
detected by the UE may be a set of some PDCCH formats, or all PDCCH
formats supported by the LTE system. The PDCCH format may be
effective on specific UE, or may be effective on a specific group
of UEs, for example, UE capable of data communication on the
unlicensed spectrum, or may be effective on all UEs accessing a
cell. A PDSCH format detected by the UE may be indicated by the
PDCCH. When a data transmission time is less than 1 ms, data
transmission of the UE may be supported by rate matching. The PDCCH
format and a rate matching rule may be learned by the UE in a
manner of signaling notification, predefinition, network
configuration, or the like.
[0286] FIG. 12 is a schematic block diagram of a data transmission
device according to an embodiment of the present invention. As
shown in FIG. 12, the data transmission device 120 in FIG. 12
includes a detection unit 121, a determining unit 122, and a
receiving unit 123.
[0287] The detection unit 121 is configured to detect a first
signal in a first cell.
[0288] The determining unit 122 is configured to determine a
reference time point according to a first sequence of the detected
first signal, where the reference time point is located in a first
subframe of the first cell.
[0289] The determining unit 122 is further configured to determine
a position of a data channel according to the determined reference
time point.
[0290] The receiving unit 123 is configured to receive, according
to the position of the data channel, control data and/or service
data carried on the data channel.
[0291] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
[0292] Each unit of the data transmission device 120 may implement
each process of the method in FIG. 2 to FIG. 10. Details are not
described again for avoiding repetition.
[0293] Optionally, in an embodiment, the determining unit 122 may
determine the reference time point according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0294] Optionally, in another embodiment, the determining unit 122
may determine the reference time point according to an index of a
symbol that is in the first cell and closest to a position of the
first sequence.
[0295] Optionally, in another embodiment, the determining unit 122
may determine the reference time point according to an index of a
symbol that is in a second cell and closest to a position of the
first sequence, where the second cell and the first cell are
deployed on different spectrum resources.
[0296] Optionally, in another embodiment, the position of the first
sequence includes a start time position of the first sequence or an
end time position of the first sequence.
[0297] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is not less than X1, the determining unit 122 may
determine that the position of the data channel is located in the
first subframe, where X1 is a time length that is not less than
0.
[0298] Optionally, in another embodiment, the determining unit 122
may further determine that a time length of a second signal is M1,
where the second signal includes the first signal, and M1 is a
minimum time length of the second signal.
[0299] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is less than X2, the determining unit 122 may
determine that the position of the data channel is located in a
second subframe, where the second subframe is a next subframe
adjacent to the first subframe; or if a time length between the
determined reference time point and an end boundary of the first
subframe is less than X2, the determining unit 122 may determine
that the position of the data channel is located in a third
subframe, where the third subframe is a next subframe that is in
the second cell and adjacent to the first subframe in time, and the
second cell and the first cell are deployed on different spectrum
resources; where X2 is a time length that is not less than 0.
[0300] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is not less than Y1, the determining unit 122
may determine that a time length of a second signal is Z1, where
the second signal includes the first signal, Z1 belongs to a length
set {L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of
the second signal is located at the end boundary of the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a
time length that is not equal to X2 and not less than 0.
[0301] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y2, the determining unit 122 may
determine that a time length of a second signal is Z2, where the
second signal includes the first signal, Z2 belongs to a length set
{L.sub.1', L.sub.2', . . . L.sub.n'}, an end time position of the
second signal is located in the second subframe of the first cell,
and the second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0302] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y3, the determining unit 122 may
determine that a time length of a second signal is Z3, where the
second signal includes the first signal, Z3 is less than M2, an end
time position of the second signal is located at the end boundary
of the first subframe, M2 is a preset minimum time length of the
second signal, and Y3 is a time length that is not equal to X2 and
not less than 0.
[0303] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is less than X3, and the time length between the
determined reference time point and the end boundary of the first
subframe is greater than Y4, the determining unit 122 may determine
that the position of the data channel is located in the first
subframe, where X3 and Y4 are time lengths that are not less than
0, and Y4 is not greater than X3.
[0304] Optionally, in another embodiment, the data channel may
carry data scheduling information of a second subframe of the first
cell, where the second subframe is a next subframe adjacent to the
first subframe.
[0305] Optionally, in another embodiment, a correspondence exists
between the reference time point and the position of the data
channel, each reference time point corresponds to one index, and
each index corresponds to one position of the data channel.
[0306] Optionally, in another embodiment, the position of the data
channel may include at least one of the following positions: a
position of a control data channel or a position of a service data
channel.
[0307] Optionally, in another embodiment, the first cell may be a
cell on an unlicensed spectrum.
[0308] FIG. 13 is a schematic block diagram of a data transmission
device according to an embodiment of the present invention. As
shown in FIG. 13, the data transmission device 130 includes a
determining unit 131 and a sending unit 132.
[0309] The determining unit 131 is configured to determine a
reference time point, where the reference time point is located in
a first subframe of a first cell.
[0310] The determining unit 131 is further configured to determine
a sending position of a first signal according to the reference
time point.
[0311] The sending unit 132 is configured to send the first signal
in the sending position of the first signal.
[0312] The determining unit 131 is further configured to determine
a position of a data channel according to the reference time
point.
[0313] The sending unit 132 is further configured to send, in the
position of the data channel, control data and/or service data
carried on the data channel.
[0314] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
[0315] Each unit of the data transmission device 130 may implement
each process of the method in FIG. 3 to FIG. 11. Details are not
described again for avoiding repetition.
[0316] Optionally, in an embodiment, the determining unit 131 may
determine the reference time point according to an index of a
symbol closest to a time point at which a spectrum resource of the
first cell is preempted.
[0317] Optionally, in another embodiment, the determining unit 131
may determine the reference time point according to an index of a
symbol that is in a second cell and closest to a time point at
which a spectrum resource of the first cell is preempted, where the
second cell and the first cell are deployed on different spectrum
resources.
[0318] Optionally, in another embodiment, the first signal may
include or carry a first sequence; and the determining unit 131 may
determine the first sequence according to the reference time
point.
[0319] Optionally, in another embodiment, the determining unit 131
may determine the first sequence according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0320] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is not less than X1, the determining unit 131 may determine that
the position of the data channel is located in the first subframe,
where X1 is a time length that is not less than 0.
[0321] Optionally, in another embodiment, the determining unit 131
may further determine that a time length of a second signal is M1,
where the second signal includes the first signal, and M1 is a
minimum time length of the second signal.
[0322] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is less than X2, the determining unit 131 may determine that the
position of the data channel is located in a second subframe, where
the second subframe is a next subframe adjacent to the first
subframe.
[0323] Alternatively, if a time length between the reference time
point and an end boundary of the first subframe is less than X2,
the determining unit 131 may determine that the position of the
data channel is located in a third subframe, where the third
subframe is a next subframe that is in the second cell and adjacent
to the first subframe in time, and the second cell and the first
cell are deployed on different spectrum resources. X2 is a time
length that is not less than 0.
[0324] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is not less than Y1, the determining unit 131 may
determine that a time length of a second signal is Z1, where the
second signal includes the first signal, Z1 belongs to a length set
{L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of the
second signal is located at the end boundary of the first subframe,
where n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0325] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is less than Y2, the determining unit 131 may determine
that a time length of a second signal is Z2, where the second
signal includes the first signal, Z2 belongs to a length set
{L.sub.1', L.sub.2', . . . L.sub.n'}, an end time position of the
second signal is located in the second subframe of the first cell,
and the second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0326] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is less than Y3, the determining unit 131 may determine
that a time length of a second signal is Z3, where the second
signal includes the first signal, Z3 is less than M2, an end time
position of the second signal is located at the end boundary of the
first subframe, M2 is a minimum time length of the second signal,
and Y3 is a time length that is not equal to X2 and not less than
0.
[0327] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is less than X3, and the time length between the reference time
point and the end boundary of the first subframe is greater than
Y4, the determining unit 131 may determine that the position of the
data channel is located in the first subframe, where X3 and Y4 are
time lengths that are not less than 0, and Y4 is not greater than
X3.
[0328] Optionally, in another embodiment, the data channel carries
data scheduling information of a second subframe of the first cell,
where the second subframe is a next subframe adjacent to the first
subframe.
[0329] Optionally, in another embodiment, a correspondence may
exist between the reference time point and the position of the data
channel, each reference time point corresponds to one index, and
each index corresponds to one position of the data channel.
[0330] Optionally, in another embodiment, the position of the data
channel may include at least one of the following positions: a
position of a control data channel or a position of a service data
channel.
[0331] Optionally, in another embodiment, the first cell may be a
cell on an unlicensed spectrum.
[0332] FIG. 14 is a schematic block diagram of a communications
device according to another embodiment of the present invention. As
shown in FIG. 14, the communications device 140 includes a
processor 141, a memory 142, a receiving circuit 143, and a
transmitting circuit 144. The processor 141, the memory 142, the
receiving circuit 143, and the transmitting circuit 144 are
connected by a system bus 149.
[0333] In addition, the communications device 140 may further
include an antenna 145, and the like. The processor 141 controls an
operation of the communications device 140. The memory 142 may
include a read-only memory and a random access memory, and provide
an instruction and data to the processor 141. A part of the memory
142 may further include a non-volatile random access memory
(NVRAM). In a specific application, the transmitting circuit 144
and the receiving circuit 143 may be coupled to the antenna 145.
Components in the communications device 140 are coupled together by
using the bus system 149. The bus system 149 may further include a
power bus, a control bus, and a status signal bus, in addition to a
data bus. However, for clear description, various buses in the
figure are marked as the bus system 149.
[0334] The processor 141 may be an integrated circuit chip and have
a signal processing capability. The processor 141 may be a general
purpose processor, a digital signal processor (DSP), an
application-specific integrated circuit (ASIC), a field
programmable gate array (FPGA), or another programmable logic
device, discrete gate or transistor logic device, or discrete
hardware component. The processor may implement or execute methods,
steps, and logic block diagrams disclosed in the embodiments of the
present invention. The general purpose processor may be a
microprocessor, or the processor may be any conventional processor
or the like. The processor 141 reads information in the memory 142,
and controls each component of the modulation device 140 with
reference to hardware of the processor 141.
[0335] The method in FIG. 2 to FIG. 10 may be implemented in the
communications device 140 in FIG. 14, or the data transmission
device in FIG. 12 may be implemented by the communications device
140 in FIG. 14. An example of the communications device 140 is user
equipment or a base station. Details are not described again for
avoiding repetition.
[0336] Specifically, the receiving circuit 143 may detect a first
signal in a first cell. The processor 141 may determine a reference
time point according to a first sequence of the detected first
signal, where the reference time point is located in a first
subframe of the first cell.
[0337] For example, the receiving circuit 143 may detect the first
signal by detecting energy of the first signal. Alternatively, in
another implementation manner, the receiving circuit 143 may simply
buffer the first signal, and the processor 141 performs detection
processing on the first signal.
[0338] The processor 141 may further determine a position of a data
channel according to the determined reference time point.
[0339] The receiving unit 143 may receive, according to the
position of the data channel, control data and/or service data
carried on the data channel.
[0340] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
[0341] Optionally, in an embodiment, the processor 141 may
determine the reference time point according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0342] Optionally, in another embodiment, the processor 141 may
determine the reference time point according to an index of a
symbol that is in the first cell and closest to a position of the
first sequence.
[0343] Optionally, in another embodiment, the processor 141 may
determine the reference time point according to an index of a
symbol that is in a second cell and closest to a position of the
first sequence, where the second cell and the first cell are
deployed on different spectrum resources.
[0344] Optionally, in another embodiment, the position of the first
sequence includes a start time position of the first sequence or an
end time position of the first sequence.
[0345] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is not less than X1, the processor 141 may determine
that the position of the data channel is located in the first
subframe, where X1 is a time length that is not less than 0.
[0346] Optionally, in another embodiment, the processor 141 may
further determine that a time length of a second signal is M1,
where the second signal includes the first signal, and M1 is a
minimum time length of the second signal.
[0347] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is less than X2, the processor 141 may determine
that the position of the data channel is located in a second
subframe, where the second subframe is a next subframe adjacent to
the first subframe; or if a time length between the determined
reference time point and an end boundary of the first subframe is
less than X2, the processor 141 may determine that the position of
the data channel is located in a third subframe, where the third
subframe is a next subframe that is in the second cell and adjacent
to the first subframe in time, and the second cell and the first
cell are deployed on different spectrum resources; where X2 is a
time length that is not less than 0.
[0348] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is not less than Y1, the processor 141 may
determine that a time length of a second signal is Z1, where the
second signal includes the first signal, Z1 belongs to a length set
{L.sub.1, L.sub.2, . . . L.sub.n}, and an end time position of the
second signal is located at the end boundary of the first subframe,
where n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0349] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y2, the processor 141 may determine
that a time length of a second signal is Z2, where the second
signal includes the first signal, Z2 belongs to a length set
{L.sub.1', L.sub.2', . . . L.sub.n'}, an end time position of the
second signal is located in the second subframe of the first cell,
and the second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0350] Optionally, in another embodiment, if the time length
between the determined reference time point and the end boundary of
the first subframe is less than Y3, the processor 141 may determine
that a time length of a second signal is Z3, where the second
signal includes the first signal, Z3 is less than M2, an end time
position of the second signal is located at the end boundary of the
first subframe, M2 is a preset minimum time length of the second
signal, and Y3 is a time length that is not equal to X2 and not
less than 0.
[0351] Optionally, in another embodiment, if a time length between
the determined reference time point and an end boundary of the
first subframe is less than X3, and the time length between the
determined reference time point and the end boundary of the first
subframe is greater than Y4, the processor 141 may determine that
the position of the data channel is located in the first subframe,
where X3 and Y4 are time lengths that are not less than 0, and Y4
is not greater than X3.
[0352] Optionally, in another embodiment, the data channel may
carry data scheduling information of a second subframe of the first
cell, where the second subframe is a next subframe adjacent to the
first subframe.
[0353] Optionally, in another embodiment, a correspondence exists
between the reference time point and the position of the data
channel, each reference time point corresponds to one index, and
each index corresponds to one position of the data channel.
[0354] Optionally, in another embodiment, the position of the data
channel may include at least one of the following positions: a
position of a control data channel or a position of a service data
channel.
[0355] Optionally, in another embodiment, the first cell may be a
cell on an unlicensed spectrum.
[0356] FIG. 15 is a schematic block diagram of a communications
device according to another embodiment of the present invention. As
shown in FIG. 15, the communications device 150 includes a
processor 151, a memory 152, a receiving circuit 153, and a
transmitting circuit 154. The processor 151, the memory 152, the
receiving circuit 153, and the transmitting circuit 154 are
connected by a system bus 159.
[0357] In addition, the communications device 150 may further
include an antenna 155, and the like. The processor 151 controls an
operation of the communications device 150. The memory 152 may
include a read-only memory and a random access memory, and provide
an instruction and data to the processor 151. A part of the memory
152 may further include a non-volatile random access memory
(NVRAM). In a specific application, the transmitting circuit 154
and the receiving circuit 153 may be coupled to the antenna 155.
Components in the communications device 150 are coupled together by
using the bus system 159. The bus system 159 may further include a
power bus, a control bus, and a status signal bus, in addition to a
data bus. However, for clear description, various buses in the
figure are marked as the bus system 159.
[0358] The processor 151 may be an integrated circuit chip and have
a signal processing capability. The processor 151 may be a general
purpose processor, a digital signal processor (DSP), an
application-specific integrated circuit (ASIC), a field
programmable gate array (FPGA), or another programmable logic
device, discrete gate or transistor logic device, or discrete
hardware component. The processor may implement or execute methods,
steps, and logic block diagrams disclosed in the embodiments of the
present invention. The general purpose processor may be a
microprocessor, or the processor may be any conventional processor
or the like. The processor 151 reads information in the memory 152,
and controls each component of the modulation device 150 with
reference to hardware of the processor 151.
[0359] The method in FIG. 3 to FIG. 11 may be implemented in the
communications device 150 in FIG. 15, or the data transmission
device in FIG. 13 may be implemented by the communications device
150 in FIG. 15. An example of the communications device 150 is user
equipment or a base station. Details are not described again for
avoiding repetition.
[0360] Specifically, the processor 151 may determine a reference
time point, where the reference time point is located in a first
subframe of a first cell.
[0361] The processor 151 may further determine a sending position
of a first signal according to the reference time point.
[0362] The transmitting circuit 154 may send the first signal in
the sending position of the first signal.
[0363] The processor 151 may further determine a position of a data
channel according to the reference time point.
[0364] The transmitting circuit 154 may further send, in the
position of the data channel, control data and/or service data
carried on the data channel.
[0365] In this embodiment of the present invention, a reference
time point in a subframe is considered for determining a position
of a data channel, and therefore, the data channel is received
according to the position of the data channel. In comparison with a
manner of starting data transmission only in a next subframe
regardless of a time position in which an LTE device seizes a usage
opportunity, spectrum resources of the subframe in which the
reference time point is located can be fully used, and therefore,
spectral usage efficiency is improved.
[0366] Optionally, in an embodiment, the processor 151 may
determine the reference time point according to an index of a
symbol closest to a time point at which a spectrum resource of the
first cell is preempted.
[0367] Optionally, in another embodiment, the processor 151 may
determine the reference time point according to an index of a
symbol that is in a second cell and closest to a time point at
which a spectrum resource of the first cell is preempted, where the
second cell and the first cell are deployed on different spectrum
resources.
[0368] Optionally, in another embodiment, the first signal may
include or carry a first sequence; and the processor 151 may
determine the first sequence according to the reference time
point.
[0369] Optionally, in another embodiment, the processor 151 may
determine the first sequence according to a one-to-one
correspondence between sequence information of the first sequence
and the reference time point.
[0370] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is not less than X1, the processor 151 may determine that the
position of the data channel is located in the first subframe,
where X1 is a time length that is not less than 0.
[0371] Optionally, in another embodiment, the processor 151 may
further determine that a time length of a second signal is M1,
where the second signal includes the first signal, and M1 is a
minimum time length of the second signal.
[0372] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is less than X2, the processor 151 may determine that the position
of the data channel is located in a second subframe, where the
second subframe is a next subframe adjacent to the first
subframe.
[0373] Alternatively, if a time length between the reference time
point and an end boundary of the first subframe is less than X2,
the processor 151 may determine that the position of the data
channel is located in a third subframe, where the third subframe is
a next subframe that is in the second cell and adjacent to the
first subframe in time, and the second cell and the first cell are
deployed on different spectrum resources. X2 is a time length that
is not less than 0.
[0374] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is not less than Y1, the processor 151 may determine that
a time length of a second signal is Z1, where the second signal
includes the first signal, Z1 belongs to a length set {L.sub.1,
L.sub.2, . . . L.sub.n}, and an end time position of the second
signal is located at the end boundary of the first subframe, where
n is an integer that is not less than 1, .A-inverted.i,
1.ltoreq.i<n, L.sub.i<L.sub.i+1, and Y1 is a time length that
is not equal to X2 and not less than 0.
[0375] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is less than Y2, the processor 151 may determine that a
time length of a second signal is Z2, where the second signal
includes the first signal, Z2 belongs to a length set {L.sub.1',
L.sub.2', . . . L.sub.n'}, an end time position of the second
signal is located in the second subframe of the first cell, and the
second subframe is the next subframe adjacent to the first
subframe, where n is an integer that is not less than 1,
.A-inverted.i, 1.ltoreq.i<n, L.sub.i'<L.sub.i+1', and Y2 is a
time length that is not equal to X2 and not less than 0.
[0376] Optionally, in another embodiment, if the time length
between the reference time point and the end boundary of the first
subframe is less than Y3, the processor 151 may determine that a
time length of a second signal is Z3, where the second signal
includes the first signal, Z3 is less than M2, an end time position
of the second signal is located at the end boundary of the first
subframe, M2 is a minimum time length of the second signal, and Y3
is a time length that is not equal to X2 and not less than 0.
[0377] Optionally, in another embodiment, if a time length between
the reference time point and an end boundary of the first subframe
is less than X3, and the time length between the reference time
point and the end boundary of the first subframe is greater than
Y4, the processor 151 may determine that the position of the data
channel is located in the first subframe, where X3 and Y4 are time
lengths that are not less than 0, and Y4 is not greater than
X3.
[0378] Optionally, in another embodiment, the data channel carries
data scheduling information of a second subframe of the first cell,
where the second subframe is a next subframe adjacent to the first
subframe.
[0379] Optionally, in another embodiment, a correspondence may
exist between the reference time point and the position of the data
channel, each reference time point corresponds to one index, and
each index corresponds to one position of the data channel.
[0380] Optionally, in another embodiment, the position of the data
channel may include at least one of the following positions: a
position of a control data channel or a position of a service data
channel.
[0381] Optionally, in another embodiment, the first cell may be a
cell on an unlicensed spectrum.
[0382] A person of ordinary skill in the art may be aware that, in
combination with the examples described in the embodiments
disclosed in this specification, units and algorithm steps may be
implemented by electronic hardware or a combination of computer
software and electronic hardware. Whether the functions are
performed by hardware or software depends on particular
applications and design constraint conditions of the technical
solutions. A person skilled in the art may use different methods to
implement the described functions for each particular application,
but it should not be considered that the implementation goes beyond
the scope of the present invention.
[0383] It may be clearly understood by a person skilled in the art
that, for the purpose of convenient and brief description, for a
detailed working process of the foregoing system, apparatus, and
unit, reference may be made to a corresponding process in the
foregoing method embodiments, and details are not described.
[0384] In the several embodiments provided in this application, it
should be understood that the disclosed system, apparatus, and
method may be implemented in other manners. For example, the
described apparatus embodiment is merely exemplary. For example,
the unit division is merely logical function division and may be
other division in actual implementation. For example, a plurality
of units or components may be combined or integrated into another
system, or some features may be ignored or not performed. In
addition, the displayed or discussed mutual couplings or direct
couplings or communication connections may be implemented by using
some interfaces. The indirect couplings or communication
connections between the apparatuses or units may be implemented in
electronic, mechanical, or other forms.
[0385] The units described as separate parts may or may not be
physically separate, and parts displayed as units may or may not be
physical units, may be located in one position, or may be
distributed on a plurality of network units. Some or all of the
units may be selected according to actual needs to achieve the
objectives of the solutions of the embodiments.
[0386] In addition, functional units in the embodiments of the
present invention may be integrated into one processing unit, or
each of the units may exist alone physically, or two or more units
are integrated into one unit.
[0387] When the functions are implemented in the form of a software
functional unit and sold or used as an independent product, the
functions may be stored in a computer-readable storage medium.
Based on such an understanding, the technical solutions of the
present invention essentially, or the part contributing to the
prior art, or some of the technical solutions may be implemented in
a form of a software product. The software product is stored in a
storage medium, and includes several instructions for instructing a
computer device (which may be a personal computer, a server, or a
network device) to perform all or some of the steps of the methods
described in the embodiments of the present invention. The
foregoing storage medium includes: any medium that can store
program code, such as a USB flash drive, a removable hard disk, a
read-only memory (ROM, Read-Only Memory), a random access memory
(RAM, Random Access Memory), a magnetic disk, or an optical
disc.
[0388] The foregoing descriptions are merely specific
implementation manners of the present invention, but are not
intended to limit the protection scope of the present invention.
Any variation or replacement readily figured out by a person
skilled in the art within the technical scope disclosed in the
present invention shall fall within the protection scope of the
present invention. Therefore, the protection scope of the present
invention shall be subject to the protection scope of the
claims.
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